Research and Resource Management at Audubon … Kelly, PhD, Director, Research & Resource Management Rebecca Anderson-Jones, Bouverie Preserve Katie Etienne, Research Coordinator

◗ 25 years of heron

and egret monitoring

Marin Islands

◗ tidal return

Livermore Marsh

◗ population

explosion

introduced

turkeys

◗ bird biodiversity

report Tomales

Bay

◗ ACR’s other

science agenda

visiting

investigators

2003

the ArdeidResearch and

Resource Management

at Audubon Canyon Ranch

Audubon Canyon RanchResearch and ResourceManagement

Executive StaffSkip Schwartz, Executive DirectorJohn Petersen, Associate DirectorYvonne Pierce, Administrative DirectorStaff BiologistsJohn Kelly, PhD, Director, Research & Resource

ManagementRebecca Anderson-Jones, Bouverie PreserveKatie Etienne, Research CoordinatorDaniel Gluesenkamp, PhD, Habitat Protection and

Restoration SpecialistGwen Heistand, Bolinas Lagoon PreserveLand StewardsBill Arthur, Bolinas Lagoon PreserveDavid Greene, Tomales Bay propertiesJohn Martin, Bouverie PreserveField BiologistsEllen BlusteinNathan FarnauLauren HammackMichael ParkesData ManagementAnnie BaileyMelissa DavisResearch AssociatesJules EvensGrant FletcherRachel KammanFlora MacliseHelen PrattRich StallcupResource Management AssociatesLen BluminRoberta DowneyScientific Advisory PanelSarah Allen, PhDPeter Connors, PhDJules EvensKent Julin, PhDGreg KammanRachel KammanChris Kjeldsen, PhDDoug Oman, PhDHelen PrattW. David ShufordRich StallcupWesley W. Weathers, PhD

the ARDEID 2002

Dawn Adams (H); Drew Alden (R); DarciAlderson (R); Kathy Allen (R); Sarah Allen (S);Leslie Allen (R); Marie Anderson (R); JudithAnna (R); Richard Arendt (R); ChristinaAttwood (R); Audrey Ayers (R); AudubonCanyon Ranch - Bouverie Preserve JuniperClub (N); Autodesk employees (R); AlexAylward (N); Bruce Bajema (HSW); Bob Baez(SW); Norah Bain (H); Annie Bailey (MR); TedBakkilla (R); Sharon Bale (R); Ryan Bartling (R);Steve & Melinka Bates (R); Tom Baty (W);Anne Baxter (H); Denali Beard (R); BrianBelsarti (R); Evelyn Berger (R); Gordon Bennett(SW); Shelly Benson (R); Louise and ShermanBielfelt (NR); Gay Bishop (S); Jeffrey Black (R);Sara Blauman (H); Julie Blumenthal (W); LenBlumin (RW); Patti Blumin (HR); EllenBlustein (MS); Noelle Bon (HN); JanetBosshard (H); Phillip Bowman (R); EmilyBrockman (HSW); Ken Burton (SW); DeniseCadman (H); Sean Cain (R); Alexa Carlson (N);Barbara Carlson (NR); Bill Carlson (N); JoyceCarlson (N); Kimberley Carlson (H); MelissaCarlson (N); Kate Carolan (SW); Ann Cassidy(H); Dave Chalk (R); Roberta Chan (R); MarieClaire Chapman (R); Giulianna Chierici (N);Tim Coates (R); Bonnie Sue Coburn (R); SteveCochrane (R); Emily Coletta (NR); CaroleConnell (H); Michelle Coppoletta (R); JeffCorbin (R); Phil Cordle (R); JoAnn Craig (R);Caitlin Cornwall (R); Helen Cravens (R); CarolCree (R); Pack 16, Den 1 Cub Scouts (R); RigCurrie (S); Linda Curry (R); Julie Dabbs (R);Fran Danoff (R); Melissa Davis (HS); CheriDegenhardt (R); Nick Degenhardt (H); MaryDespain (R); Giselle Downard (H); RobertaDowney (R); Joe Drennan (W); Don and ElaineDvorak (M); Bob Dyer (H); David Easton (H);Lance Eberling & 25 Boy Scouts and parents(R); Cathy Evangelista (H); Jules Evens (RSW);Nathan Farnau (S); Jim Farnkoph (R); KatieFehring (SW); John Finger (R); Binny Fischer(HW); Chris Flannagen (R); Grant & GinnyFletcher (HPSW); Carol Fraker (H); JamieFreymuth (R); Audrey & Randy Fry (R); Donna& Lia Gaetano (R); Daniel George (S); JohnGeraci (R); Tony Gilbert (HSW); Keith Gish (H);Beryl & Dohn Glitz (H); Ivy Gluesenkamp (R);Marilyn Goode (R); Geri Gotterath (R); PhilipGreene (H); Beth Gurney (R); Karlene Hall (R);Lauren Hammack (M); Madelon Halpern (H);Roger Harshaw (S); Bill Haycock (R); Mike &Janaea Henkes (R); Diane Hichwa (HS);Raymon & Janet Higgins (R); Tom Highland(R); Anne Hillsley (R); Diana & HannahHindley (R); Jake Hobson (H); Helen Howard(R); Steve Howell (W); Lisa Hug (SW); DaschaInciarte (R); Ellie Insley (R); Jeri Jacobson (H);Barbara Janis (R); Calvin Jones (R); Lea Jordan(R); Gail Kabat (W); Lynnette Kahn (HS); PattyKarlin (H); Bob Kaufman (H); Guy Kay (H);Carol Keiper (S); Marion Kirby (N); Richard

Kirschman (S); Nolan Kloer (R); Ellen Krebs(H); Carol Kuelper (S); Amanda Kurt (R); AndyLaCasse (H); Sherry Lambert (R); JoanLamphier (H); John Larson (R); Olim Leasher(R); Bill Lenzarz (H); Robin Leong (H); EileenLibby (H); Patricia Lonacker (R); Flora Maclise(H); Phil Madden (R); Art & Lynn Magill (R);Donovan Maloney (N); Jean Mann (R); AlanMargolis (R); Roger Marlowe (W); SandyMartensen (R); Connor Martinelli (N); NancyMavis (R); Chris Mc Auliffe (H); Ann McDenna(R); Pat McLorie (NR); Diane McLure (R);Pamela Mears (R); Jean Miller (H); JamesMiramontez (R); Judy Missakian (H); AndrewMorado (N); Sully Mynatt (R); Ken Neihoff (R);Dexter Nelson (R); Wally Neville (H); MarkNewhouser (T); Ben & Kay Nippes (R); TerryNordbye (S); Clara Obstfeld (R); Mary O’Hern(R); Brandon Orr (R); Judy Osborn-Shaw (R);Briggitta Page (R); Richard Panzer (H); JenniePardi (H); Bob Parker (R); Mike Parkes(HRSW); Patagonia employees (R); Joelle &James Peebles (R); Sara & Dan Penn (R);Carina Peritore (R); Kathy Peterlein (S); SallyPola (R); Stephen Pomeroy (R); MyrleePotosnak (H); Nancy Proctor (R); Sue EllenRaby (R); Julia Reagan (N); Paula Rector (R);Linda & Jeff Reichel (H); Anne Reynolds (R);Sally A. Reynolds (R); Betty Rice (R); RobinRichard (N); Rudi Richardson (W); TinaRichardson (R); Richard Riopelle (R); John &Sally Risberg (R); Gaius Robinson (R); TeresaRodgers (R); Barbara & Mike Rosen (R); GlendaRoss (R); Liz Ruellan (R); De Ann Rushall (RT);Janel Russing (R); Tom Rutkowski (R); LenaRyberg (R); Ellen Sabine (HS); Marilyn Sanders(HR); Fran Scarlett (H); Cindy Schafer (S);Phyllis Schmitt (R); Janette Schue (R); AliceSchultz (H); Craig Scott (S); Asha Setty (R);Sierra Club “Outings” (R); Bob Smith (S); ErnieSmith (R); Joe Smith (HW); Anne Spencer (S);Rich Stallcup (S); Jean Starkweather (H);Caroline Starrs (N); Michael Stevenson (S);Sandy Stoddard (R); David Stokes (T); Ron &Helen Sundergill (R); Lowell Sykes (HSW);James Tanforan (R); Judy Temko (HS); Evelyn &Lisa Teot (R); Janet Thiessen (H); Bill Thomson(H); Gil Thomson (H); Dodie Thomson (H);Traci Tinder (R); Alicia Toldi (T); Leigh Toldi(T); Sue Tredick (H); Susan Tremblay (R); JoanTurner (R); Rosemary Uren (R); Sue Van DerWal (H); Roberta Varble (R); Zoltan Vasvary (R);Linda Vida (R); Norma Vite (R); Sasha Vitomski(R); Liang Wang (H); Loraine Walsh (R); TanisWalters (HS); Penny Watson (W); SueWeingarten (R); Arlene Weis (R); Patrick Welch(H); Wells Fargo employees (R); Kile White(NR); Rosilyn & Tom White (W); DianeWilliams (S); Ken Wilson (HW); Jon Winter (H);Rollye Wiskerson (H); Mike & Jane Witkowski(R); Katy Zaremba (R).

In this issue

A Tale of Two Islands: 25 years of monitoring heron and egret monitoring at the Marin Islands ◗by John P. Kelly ......................................................................................................................page 1

The Return of Tidal Circulation: Breeding and winter bird use in Livermore Marsh◗by Katie Etienne......................................................................................................................page 4

Introduced Turkeys: California’s latest population explosion ◗by Daniel Gluesenkamp ....page 6

Bird Alphabet Soup: A report on the All Taxa Biodiversity Inventory of Tomales Bay ◗by John P. Kelly ......................................................................................................................page 8

The Other Scientific Agenda: Visiting investigators on ACR lands ◗by John P. Kelly ........page 13

In Progress: Project updates ◗ ................................................................................................page 15

Cover photo: Common Goldeneye by Kenneth W. Gardiner ◗ Ardeid masthead Great Blue Heron ink wash painting by Claudia Chapline

Volunteers for ACR research or habitat restoration projects since TheArdeid 2002. Please call (415) 663-8203 if your name should have beenincluded in this list.

PROJECT CLASSIFICATIONS:

H = Heron/Egret Project ◆ M = Livermore Marsh Monitoring ◆ N = NewtSurvey ◆ P = Photo Points ◆ R = Habitat Restoration ◆ S = Tomales BayShorebird Project ◆ T = Turkey Project ◆ W = Tomales Bay Waterbird Census

The Watch

2003 the ARDEID page 1

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Twenty-five years of heron and egret monitoring at the Marin Islands

A Tale of Two Islandsby John P. Kelly

The Marin Islands rise steeply from the bay shallows nearSan Rafael, like displaced chunks of the surroundinghills. One is forested with eucalyptus and pines;the other is grassy and more open, but lushbuckeye and blackberry canopies mantlethe northeast side, and these areadorned each spring and summerwith hundreds of nesting heronsand egrets. The islands are beau-tiful. Relatively undisturbedrelicts of an earlier time, they sitjust off the mostly urbanizedshoreline of the SanFrancisco Estuary, areminder that the lives ofbirds and humans areintertwined. And in theclassic words used byDickens to portray socie-tal extremes, the heronryhas seen “the best of times”and “the worst of times.”

Figure 1. West Marin Island is thickly dottedwith nesting Great Egrets and Snowy Egrets and

supports less conspicuous colonies of Black-crowned Night-Herons and Great Blue Herons.

Continued on page 2

In 1979, Helen Pratt and others fromthe Marin Audubon Society began moni-toring the numbers of nesting herons andegrets on West Marin Island (Figure 1). In1993, when the Marin Islands became aNational Wildlife Refuge, AudubonCanyon Ranch began making repeatedvisits each nesting season to track thereproductive performance of individualGreat Egrets and Great Blue Herons (Kellyet al. 1994–1997, Kelly and Fischer1998–2003). As many as 900 pairs ofherons and egrets settle on West MarinIsland in a good year—a concentration ofreproductive activity that stands out dis-tinctly among heronries in the SanFrancisco Bay area (more than 60 heron-ries are monitored each year by ACR;Kelly et al. 1993). The Marin Islands maytherefore have a strong influence on thedynamics of regional heron and egretpopulations. With this potentially criticalrole of the heronry in mind, observers ofthe Marin Islands have experienced sea-sons of hope as well as seasons of despair.

Keeping watch

Each year, Binny Fischer and I mapthe locations of Great Egret andGreat Blue Heron nests on

panoramic photographs. We use tele-scopes to monitor nest survivorship, sea-sonal timing based on behavioral stages,and number of young fledged from thenumbered nests. To count the numbers ofnests, we drift slowly by boat around thecolony and then compare totals with esti-mates made with telescopes from EastMarin Island. Great Blue Herons typicallynest on the highest branches, and theyoften land conspicuously on the highestperches as they approach their nest sites.Great Egrets build nests everywhere onthe outer surface of tree canopies, withone to four young per nest standingpatiently among the ubiquitous whitecatkins of the buckeyes. Black-crownedNight-Herons and Snowy Egrets oftenconceal their nests beneath blackberry orpoison oak and go undetected during ourcounts. However, comparisons with aerial

photographs and colony-based countsindicate that our annual surveys effective-ly track changes in colony size.Colony size trends and variability

Occasionally, herons and egrets flyto East Marin Island to collect neststicks. With the exception of one

(failed) Great Blue Heron Nest in 1999,heron and egret nests are established onlyon the western island. Yearly fluctuationsin the number of heron and egret nestshave been considerable (Figure 1). This isexpected, however, because colonialherons and egrets belong to larger popu-lations that shift annually in their relativeuse of colony sites.

To further complicate explanations ofannual differences, local influences mayor may not affect nesting densities. On 4July 1981, a fire burned about 1.5 acres ofnesting habitat on the northwest slope ofthe West Marin Island, killing about 100young Snowy Egrets and Black-crownedNight-Herons (Pratt 1983). Even so, nest-ing densities in subsequent years

page 2 the ARDEID 2003

remained high (Figure 1). InJuly 1955, 53 egrets (mostlyGreats and a few Snowies)were “wantonly slaugh-tered…by rifle-bearing targetshooters” (Pratt 1993). Theculprits were arrested and,fortunately, egrets continuedto nest on the island. Short-term increases and declinesin the numbers of GreatEgrets nesting on West MarinIsland have occurred but nolong-term trends are evident(Figure 1), and the productivi-ty of Great Egrets has beenfairly stable (Figure 2). Thesepatterns are encouraging,especially in light of recently

intense nest predation by CommonRavens, which has been a regular fact oflife in the heronry since 1993 (see below).

Regional dynamics

Black-crowned Night-Herons at WestMarin Island have shown a gradualdecline, followed by possible recov-

ery over recent years (Figure 1). But wehave seen reciprocal changes in the num-ber of night-herons on Alcatraz and otherislands in the bay. As nesting distributionsshift, smaller heronries are more likely tobe abandoned. More rarely, herons andegrets may desert large colony sites, suchas Bair Island in South San Francisco Bay,which was abandoned after heavy preda-tion by non-native red fox. So, regionalpopulations are more stable than suggest-ed by the fluctuating numbers at theMarin Islands or other sites. Great BlueHerons began nesting on West MarinIsland in 1990, soon after a nearby heroncolony was abandoned.

The shifting distribution of SnowyEgrets clearly illustrates the regional con-nectivity of heronries. In 1993, Snowiesbegan drifting away from West MarinIsland to other colonies in the region(Figure 3). The shift was apparently theresult of repeated harassment by a singleRed-tailed Hawk (we found no evidenceof predation). The mischievous hawkcaused frequent fly-ups of Snowies forweeks during their early stages ofcourtship and nest initiation. This harass-ment continued into 1994, when finallyall but eight pairs of Snowies abandonedthe island. Coincidental increases in thenumbers of Snowy Egrets soon becameevident at several other colonies in theregion, from nearby Red Rock and BrooksIslands to distant sites in Napa Countyand Suisun Marsh. The number of

Figure 1. Number of active heron and egret nests observed onWest Marin Island, 1979–2002.

Figure 2. Number of Great Egret young produced per nest at West MarinIsland, 1993–2002 (mean prefledging brood size adjusted for overall nestsurvivorship; error bars = standard errors).

Great Egret

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Great Egret Number of young fledged per nest attempt

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Snowy Egret

Great Blue Heron

Black-crowned Night-Heron

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0


Egrets! A predominance of Snowy Egreteggs, young, and adults among raven preyremains suggests that Snowies might suf-fer greater nest predation by ravens thanother heron or egret species, but we havenot been able to test this possibility. Bythe time fledgling ravens from the easternisland are a week old, they are flying withtheir parents to the heronry where theyspend extended periods of time, presum-ably learning to harvest heron and egreteggs and young.

Great Egret nestlings are left unattend-ed and vulnerable to raven predationwhen they reach three to four weeks ofage—when they no longer need broodingto stay warm and, presumably, both par-ents must search for food. If nestlings sur-vive to five weeks, however, they becomeso large that their vulnerability to preda-tion declines. The overall stability of theGreat Egret colony over the last decadesuggests that a heronry of this size may be

able to tolerate the preda-tory activities of residentravens. This may be possi-ble in part because someegrets renest successfullyafter failure.

Western Gulls also neston West Marin Island andoccasionally prey on heronand egret nests. Morerarely, Great-horned Owls

and even Black-crowned Night-Heronsare known to take nestling herons oregrets. However, most resident predatorsdo not seem to threaten the heronryoverall. Intense or continuing distur-bance can destroy heronries but, so far,herons and egrets at the Marin Islandshave been able to rebound from suchepisodes. Their ability to withstand suchchallenges, season after season, is per-haps good reason for hope. ■

References cited

Kelly, J.P., K.L. Etienne, and J.E. Roth. 2002.Abundance and distribution of the CommonRaven and American Crow in the San FranciscoBay area, California. Western Birds 33: 202–217.

Kelly, J.P., and B. Fischer. 1998–2003. 1997–2002heron and egret monitoring results at WestMarin Island. Annual Reports to the San PabloBay National Wildlife Refuge.

Kelly, J.P., B. Fischer, and H.M. Pratt. 1994–1997.1993–1996 heron and egret monitoring resultsat West Marin Island. Annual reports to the SanFrancisco Bay National Wildlife Refuge.

Kelly, J.P., H.M. Pratt, and P.L. Greene. 1993. Thedistribution, reproductive success, and habitatcharacteristics of heron and egret breedingcolonies in the San Francisco Bay area. ColonialWaterbirds 16(1): 18–27.

Kelly, J.P., and J.E. Roth. 2001. Audubon CanyonRanch raven project progress report,December 2001. Audubon Canyon Ranch Tech.Rpt. 98-9-2.

Pratt, H.M. 1983. Marin County California heroncolonies: 1967–1981. Western Birds 14: 169–184.

Pratt, H. M. 1993. Bitterns and herons: FamilyArdeidae. Pages 91–102 in Shuford, W.D., TheMarin County Breeding Bird Atlas. BushtitBooks, Bolinas, CA 94924.

Snowies nesting on West Marin Island hasgradually recovered in recent years, per-haps partly because of previous breedersreturning to the island and partly becauseof an apparent regional increase inrecruitment (Figure 3).

Resident predators

Common Ravens nest each year onEast Marin Island, frequentlyspending time in the heronry on

West Marin Island. Dramatic increases inthe numbers of Common Ravens in theSan Francisco Bay area (Kelly et al. 2002)have focused concerns over possibleincreases in nest predation by CommonRavens in heronries (Kelly and Roth 2001).

Shell fragments and caches of foodfound near the raven nest confirm fre-quent pilfering of heron and egret eggs.Last year, we discovered prey remainsindicating that resident ravens had cap-tured and eaten at least 15 adult Snowy

Snowy Egret

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Figure 3. Number of active Snowy Egret nests at colony sites in the northern San Francisco Bay area, 1991–2002. The presence of a single Red-tailed Hawk onthe Marin Islands in 1993–1994 coincided with regional shifts in nesting distribution.

Active Snowy Egret nests

Petaluma

Bodega Harbor

Alcatraz Island

Red Rock

Suisun Marsh

Santa Rosa Creek

Penngrove

Bolinas Lagoon (ACR)

Napa State Hospital

Brooks Island

West Marin Island

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Red-tailed Hawk


As I set aside competing thoughts andinhale the morning breeze sweepingacross the east shore of Tomales Bay, Ibecome aware of the diverse communityof birds that have been active since firstlight. I move very slowly, until EllenBlustein reminds me to walk at a moder-ate speed while she records the positionof each bird. We follow an establishedroute, weaving among tules, willows, andsedges. If a bird utters an alarm call, Ellenpauses briefly to identify all birds respond-ing to the call, and pays particular atten-tion to departing birds to avoid countingthem again in different locations. Ellen’stalent for recalling song fragments, key

physical characteristics,and subtle behavioralclues are crucial for aneffective census. The eightwinter and eight breedingbird counts conductedeach year are part of afive-year research projectby Audubon CanyonRanch (ACR) to examinephysical changes, vegeta-tion structure, and birduse after the reintroduc-tion of tidal circulation inLivermore Marsh.

Following the storm-water breech of the North Pacific CoastRailroad levee at Cypress Grove in 1998,the temporary freshwater marsh wastransformed into a gradient of fresh,brackish, and tidal conditions. The pro-portions of these wetland types are deter-mined by changes in the elevation of themarsh plain and developing tide chan-nels, which are measured periodicallywith topographic surveys (see Ardeid2001). We anticipated that this tidalrestoration project would also alter thevegetation in the lower marsh and reducethe use of the marsh by some bird species,but we recognized that a self-maintainingtidal marsh will eventually support a netincrease in overall biodiversity. Previousstudies by John Kelly and Katie Fehring,conducted when Livermore Marsh was afreshwater system (1991–1995), providean opportunity to measure changes invegetation and avian use under develop-ing tidal conditions (1999–2003).

As predicted, the winter and breedingsurveys indicate a decline among somebird species during the first five years ofthe tidal period; a few species increasedin abundance and most of the 98 species

remained stable. However, it is importantto understand that extrinsic factors suchas weather, regional and continentalchanges in bird populations, and landuse patterns also influence current popu-lation estimates. With this caveat inmind, I invite you to consider data for 34species that are most directly affected byhabitat changes in the lower marsh. Tofacilitate this comparison, we separatedthese wetland birds into four groupsprior to analysis. Other birds species con-tinue to use the marsh but are probablyunaffected by changes in tidal conditions(see box at left). Winter and breeding bird use inthe lower marsh

The annual number of winteringspecies decreased in two of the fourgroups using the lower marsh

(Figure 1). Thirteen species of diving anddabbling ducks used Livermore Marshduring the ten study years. Winter abun-dance declined significantly for sevenduck species during the tidal period, andsix duck species were stable across allwinter counts. The only exception wasRed-breasted Merganser, which was

Breeding and winter bird use in Livermore Marsh

The Return of Tidal Circulation

by Katie Etienne

Bird species not likely to show

effects of tidal reintroduction

Many wintering, breeding (*), and visitingspecies use riparian or seasonal freshwater veg-etation that is unaltered by tidal reintroduction.

Cattle EgretGreen HeronGadwallCommon GoldeneyeOspreyTurkey VultureWhite-tailed KiteNorthern Harrier*Red-tailed HawkSharp-shinned HawkCooper’s HawkRed-shouldered HawkAmerican KestrelCalifornia Quail*Common MoorhenMourning Dove*Anna’s Hummingbird*Allen’s Hummingbird*Downy WoodpeckerNuttall’s WoodpeckerNorthern FlickerSay’s PhoebeWestern Wood-PeweeAsh-throated

FlycatcherWarbling VireoHutton’s VireoWestern Scrub-Jay*American CrowCommon RavenViolet-green SwallowNorthern Rough-

winged SwallowBarn SwallowTree SwallowCliff Swallow*Chestnut-backed

Chickadee*

Common Bushtit*Bewick’s Wren*Golden-crowned

KingletHermit ThrushAmerican RobinSwainson’s Thrush*Varied ThrushWrentit*European StarlingAmerican PipitYellow WarblerOrange-crowned

WarblerYellow-rumped

WarblerWilson’s Warbler*Spotted TowheeCalifornia Towhee*Savannah SparrowFox SparrowLincoln’s SparrowWhite-crowned

SparrowGolden-crowned

SparrowDark-eyed JuncoBlack-headed

Grosbeak*Western MeadowlarkBrewer’s Blackbird*Brown-headed

Cowbird*Northern OriolePurple Finch*House Finch*Pine SiskinAmerican Goldfinch*House Sparrow

Figure 1. Annual number ofwinter bird species in LivermoreMarsh during freshwater (1991–1995) and tidal (1999–2003)periods.

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observed only during the tidal period, inthe winters of 2000 and 2003. The loss ofpersistent (non-tidal) open water in thelower marsh probably accounts for theabsence of three species of nesting ducksduring tidal surveys (Table 1).

Ten species of shorebirds were record-ed during at least one winter survey. Thenumber of shorebird species was higherduring the 1991 census and probably cor-responds to the end of a drought that hadprevented flooding of shallow areas of themarsh plain until mid-winter. The greatervariation in shorebird richness recordedduring the tidal period probably occurredbecause censuses were not conductedduring consistent tide levels. The increasein shorebird richness during the tidalperiod is due primarily to the presence ofSpotted Sandpipers and Western Sand-pipers. The density of winter Killdeer alsoincreased significantly during the tidalperiod. In contrast, SemipalmatedPlovers, Willets, Dunlins, and Long-billedDowitchers were observed during thefreshwater period but not during the tidalperiod. Of course, these values do notrepresent changes in the populations ofthese birds, for all of these species arecommon to the Tomales Bay shorelineand are frequently observed foraging onthe expanding delta just beyondLivermore Marsh.

Audubon Canyon Ranch previouslyidentified six “Key species” for wetlandmanagement: Virginia Rail, Marsh Wren,Common Yellowthroat, Song Sparrow,Red-winged Blackbird, and TricoloredBlackbird. Although TricoloredBlackbirds typically winter in other near-by habitats and are not commonlyobserved in coastal marshes, large num-bers (250 to 500 nests!) were observed

during the freshwater period, and five ofthese species were significantly moreabundant during the freshwater versusthe tidal period, while the number ofGreat Egrets and Black Phoebes increasedduring the recent tidal period (Table 1).

Fifteen of the 34 selected species heldbreeding territories during at least onefive-year period (Table 1). CommonYellowthroat, Song Sparrow, and Killdeerhad significantly more territories duringthe tidal period, and nine territorialspecies nested in significantly greaternumbers during the freshwater period.One Sora territory was suggested by threeobservations in 1999, but evidence ofnesting Soras has not been confirmed.Virginia Rails were heard several times in2001, but vocalizations never lasted longenough to confirm territories. Never-theless, we know Virginia Rails continuedto nest in the marsh because Ellenobserved chicks in February, which indi-cates they can breed before the breedingbird censuses are conducted. Killdeerchicks were recorded only in 2003 but, aswith Belted Kingfishers and BlackPhoebes, they were known to nest innearby areas.

These observations demonstrate thedynamic changes that are occurring, andwe are encouraged that Livermore Marshcontinues to support a diverse aviancommunity. In spite of the expecteddecline in use by freshwater bird species,we look forward to the development of aself-sustaining tidal marsh with a highdiversity of plankton, zooplankton,plants, and invertebrates, and theenhanced primary and secondary pro-ductivity that drives tidal ecosystems. ■

during the breeding seasons of 1988,1989, and 1992. More Virginia Rail terri-tories were detected during the freshwa-ter period, while Marsh Wrens remainedstable year-round and Song Sparrowsreached higher winter and breeding den-sities during the tidal period.

We predicted that 14 “Other wetlandspecies” would also be influenced bychanges in the tidal regime (Figure 1).Winter richness in this group was higher

The number of Marsh Wrens using Livermoremarsh has remained stable year-round, despitetidal-induced reductions in cattail and bulrush cover.

Tidal reintroduction appears to have improved condi-tions for Song Sparrows in lower Livermore Marsh.

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Species Winter Breeding

Diving & dabbling ducksAmerican Wigeon F>TMallard F>T F>T(0)Cinnamon Teal F>T F>T(0)Northern Pintail –Northern Shoveler –Green-winged Teal F>T(0)Canvasback F>T(0)Ring-necked Duck –Greater Scaup –Bufflehead F>THooded Merganser –Red-breasted Merganser –Ruddy Duck F>T F>T(0)

ShorebirdsSemipalmated Plover –Killdeer F<T F<TGreater Yellowlegs –Willet –Spotted Sandpiper –Western Sandpiper –Least Sandpiper –Dunlin –Long-billed Dowitcher –Common Snipe –

Key speciesVirginia Rail – F>TMarsh Wren – –Common Yellowthroat – F<TSong Sparrow F<T F<TRed-winged Blackbird F>T –Tricolored Blackbird F>T(0)

Other wetland speciesPied-billed Grebe F>T F>T(0)Eared Grebe –Great Egret F<TSnowy Egret –Great Blue Heron F>TBlack-crowned Night Heron F>T(0)Sora – –American Coot F>T F>T(0)Mew Gull –Glaucus-winged Gull –Belted Kingfisher – F>TBlack Phoebe F<T F>TWinter Wren –Swamp Sparrow F>T(0)

Table 1. Winter densities and breeding bird territo-ries during freshwater (1991–1995) vs. tidal (1999–2003) conditions. Symbols indicate significantlygreater numbers during freshwater (F>T) or tidal(F<T) conditions (P <0.05). Zero (0) indicates speciesthat were absent during the tidal period. Dash (–)indicates non-significant differences. Blank indicatesabsence during both periods.


California is in many ways an eco-logical island, isolated by thePacific Ocean to the west and by

expansive deserts on the east. This isola-tion fueled tremendous innovation inCalifornia's plants, animals, and ecologi-cal communities; for example, nearly athird of California plant taxa are uniqueto the California floristic province. Thisera of isolation ended when Europeancolonization connected California to therest of the world, introducing new speciesand interactions, and presenting interest-ing challenges to preservation ofCalifornia's indigenous biodiversity.

Wild Turkeys (Meleagris gallopavo) areamong the most interesting challengesintroduced to California. Though nativeto other parts of North America, WildTurkeys never successfully colonizedCalifornia (Burger 1954), and California’secosystems have evolved in the absenceof large galliform birds.

In November 2002 I initiated the firstexperimental assessment of turkeyimpacts in California, a central compo-nent of Audubon Canyon Ranch’s TurkeyInvasion Program. The objectives of theprogram include conducting scientificexperiments to evaluate the ecologicalimpacts of introduced turkeys, mappingthe distribution and abundance ofturkeys, and working with otherresearchers, conservationists, and theDepartment of Fish and Game to learnmore about the ongoing invasion.

Introduction of turkeys to theGolden State

Introduction of turkeys to Californiabegan with an 1877 release on SantaCruz Island (Small 1994). Attempts to

establish populations for hunting con-tinued with major state-sponsoredrelease programs around 1910 andbetween 1928–1951 (Harper and Smith1970). These early introductions failed toestablish vigorous populations, probablydue to the fact that the birds releasedwere farm-raised and poorly suited tosurvive in the wild. In the early 1970sand 1980s, however, the California

Department of Fish and Game beganimporting and releasing birds of the RioGrande subspecies (M. gallopavo inter-media). These birds were wild-caught inTexas, in habitats comparable to thosefound at the California release sites, andRio Grande introductions have been verysuccessful. Populations have increasedvery rapidly, ranges have expanded dra-matically, and turkeys have become acommon component of California westof the Sierra Nevada.

Very little is known about the popula-tion and community biology of intro-duced turkeys in California, or aboutimpact on the systems that they invade.Introduced turkeys may negatively affectnative systems indirectly (by competingwith native species for resources, or viaphysical disturbance of soil and litter dur-ing foraging) or may directly impactnative species (e.g. by eating them).Cursory diet studies have shown thatintroduced turkey diets are extremelybroad. However, the nature and severityof turkey impacts are largely unknown;even in states where turkeys have beenmanaged for a century, most research has

focused on management for hunting, andsurprisingly little is known about the ecol-ogy of this beautiful animal.

Understanding the turkeyinvasion

Quantifying the ecological impactsof introduced turkeys is an impor-tant first step in determining how

to respond to this invasion. To measurethese impacts, I am using cage exclosuresto manipulate turkey abundance andexamine two pathways by which turkeyinvasion may affect ecological systems inSonoma: direct impacts via consumptionof prey items and indirect impacts of for-aging disturbance. This experiment willquantify turkey effects on vegetationstructure and composition, on inverte-brate abundance and composition, andon the consumption of specific fooditems such as acorns and salamanders.The study will also assess the utility oftools likely to be used in future turkeystudies and management programs, andwill test assumptions, such as inefficientforaging and low prey encounter rates,that have led the Department of Fish and

California’s latest population explosion

Introduced Turkeysby Daniel Gluesenkamp

Sonoma State University students participate in ACR’s turkey exclusion experiment during a RestorationEcology class field trip to the Bouverie Preserve. Biology students were taught principles of experimentaldesign as they assisted with plot set-up and initial data collection. The ongoing three-year experiment eval-uates the impact of introduced turkeys on native ecosystems.

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Game to conclude that additional turkeyintroductions will not harm rare andendangered species (DFG 2001).

While it is clear that turkey popula-tions are expanding rapidly, there arealmost no data regarding their size, theirgeographic range, or their rate ofincrease and expansion. I am currentlyplanning a project that will map theabundance and distribution of turkeys inMarin and Sonoma counties. The map-

ping work is supported by the SonomaEcology Center, ACR’s partner in thisendeavor and a respected source of GIS(Geographic Information Systems) map-ping expertise. Results of this study willprovide scientists and conservationistswith crucial information on turkey distri-bution and patterns of spread. The datawill also enable us to predict which habi-tats are likely to be most affected byturkeys and to estimate how many

turkeys we will have when populationgrowth eventually levels off.

Finally, ACR is working with others todevelop and share current information onthe status of the turkey invasion. We haveoffered ACR preserves and expertise touniversity researchers and graduate stu-dents interested in studying the ecologyand behavior of introduced turkeys. Wehelped convince the Department of Fishand Game to institute a moratorium onadditional turkey introductions, and havemet with leaders of DFG’s turkey programto discuss conservation concerns associ-ated with the spread of this non-nativeorganism. It is our hope that by develop-ing objective scientific data and then pre-senting well-supported conclusions tocitizens, conservationists, and decision-makers, Audubon Canyon Ranch willmake an important contribution to mini-mizing the impact of this new invader onCalifornia’s precious biological diversity.

References citedBurger, G.V. 1954a. The status of introduced

turkeys in California. California Fish and Game40(2): 123–145.

Burger, G.V. 1954b. Wild turkeys in central coastalCalifornia. Condor 56: 198–206.

Department of Fish and Game. 2001. Draft envi-ronmental impact report: wild turkey enhance-ment project. State of California, Department ofFish and Game, Sacramento, CA.

Harper, H.T. and W.A. Smith. 1970. California’sturkey stocking program. Pages 55–63 inSanderson, G.C. and H.C. Schultz, editors. Wildturkey management: current problems andprograms. University of Missouri Press,Columbia, Missouri.

Small, A. 1994. California Birds. Ibis Publishing Co,Vista, CA.

Smith, W.A. and B. Browning. 1967. Wild turkeyfood habits in San Luis Obispo County,California. California Fish and Game 53(4):246–253.

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AcaciaAchilleaActaeaAgoserisAgropyronAlliumAlnusAlopecurusAmaranthusAmbrosiaAmpelopsisAmphicarpaAmphicarpaeaAmsinckiaAnagallisAndropogonAneilemaAnemoneAnemopsisApiosAraliaArbutusArctiumArctostaphylosArdisiaArisaemaAristolochiaArtemesiaAsiminaAsterAstragulusAvenaAxonopusBemoinBerbisBerchemiaBetulaBidensBlepharoneuronBoutelouaBrachypodiumBrassicaBrizaBromusBumelia

CallicarpaCalochortusCarexCaryaCassiaCastaneaCeanothusCeltisCentellaCentrosemaCerastiumChenopodiumChlorisChrysobalanusCirsiumClaytoniaCleomeCommelinaCornusCrataegusCrotalariaCrotonCynodonCyperusDactylisDanthoniaDaucusDescuraimaDescuraniaDesmodiumDichelostemmaDigitariaDiodiaDiospyrosDryopterisEchinochloaElaeagnusElymusEpilobiumEquisetumEragrostisErigeronEriogonumErodiumEupatorium

EuphorbiaFagopyrumFagusFestucaForestieraFragariaFraxinusGalactiaGaliumGauraGaylussaciaGeraniumGlycineGyrothecaHamamelisHelianthusHepaticaHoffmansegiaHordeumHoustoniaHydrocotyleHymenoxysHypochaerisHypoxisIlexIpomoeaIrisIsoetesJatrophaJuncusJuniperusKoeleriaKrigiaLactucaLantanaLappulaLathyrusLeptochloaLespedezaLessingiaLiliumLiquidamberLithospermumLoliumLonicera

LotusLudwigiaLupinusLycopodiumMadiaMahoniaMedicagoMelicaMelitotusMenispermumMenodoraMicroserisMitchellaMorusMuhlenbergiaMunroaMuscadiniaMyricaNassellaNasturtiumNyssaOnocleaOnosmodiumOpuntiaOrchidaceaeOreophilaOryzopsisOsmorhizaOstryaOxalisOxypolisPanicumParthenocissusPaspalumPedicularisPerseaPhaceliaPhalanrisPhleumPhotiniaPhysalisPicrisPinusPlagiobothrysPlantago

PoaPolygonatumPolygonumPolypodiumPolypogonPolystichumPontedenriaPortulacaPotentillaProsopisPrunusPseudotsugaPsoraleaPteridophytaPterisPurshiaPyrrhopappusPyrusQuercusRanunculusRatibidaRhamnusRhusRibesRobiniaRosaRubusRudbeckiaRumexSabalSagittariaSalviaSambucusSassafrasSchismusScirpusScleriaScrophulariaSenecioSerenoaSerineaSetariaShepherdiaSileneSilybum

SisyrinchiumSmilaxSolanumSolidagoSonchusSorghumSphenopholisSporobolusStellariaStillingiaStipaiStyraxSymphoricarposTaraxacumTaxodiumTephrosiaToxicodendronTragopogonTricachneTrifoliumTriticumTsugaUlmusUmbellulariaUniolaVacciniumVaseyochloaVemoniaVerbascumVerbenaVerbesinaViburnumViciaVignaViguieraViolaVitisVulpiaXyrisZanthoxylumZeaZizanopsis

Table 1. Partial list of plant genera found in Wild Turkey food habit literature (Smith and Browning 1967,DFG 2001). Turkey gizzards grind food beyond recognition, making accurate dietary studies extremely diffi-cult, and their diets are seasonally variable. However, even incomplete dietary studies demonstrate thatintroduced turkeys consume an enormous variety of food items. Turkey dietary breadth may have dire con-sequences for native biodiversity; of 194 rare and special status plant taxa that occur in Marin and Sonomacounties, 35% (64 taxa) occur in genera listed below (CalFlora 2003). While details are less well knownthan for plants, turkeys also consume a variety of animals, including invertebrates, reptiles, amphibians, andeven other birds.

Invasive populations of Wild Turkey inCalifornia are derived from birds of the RioGrande subspecies, introduced from Texas.


How many bird species use TomalesBay? In a recent report to thePoint Reyes National Seashore,

Audubon Canyon Ranch addressed thisquestion in considerable depth, markingthe first contribution to a planned AllTaxa Biodiversity Inventory (ATBI) forTomales Bay (Kelly and Stallcup 2003).The answer to this relatively simple ques-tion is complex and conditional, depend-ing on the timing, frequency of occur-rence, distribution among sub-areas, anddetectability of species. Overall, the reportreveals a surprising richness of birds,including rare visits by several unexpect-ed species. Consider, for example, that inaddition to the typical profusion of water-birds, you have a better-than-zerochance, based on past records (Table 1),of seeing a Yellow-billed Loon, a BlackSkimmer, or even a MagnificentFrigatebird on Tomales Bay!

The Tomales Bay ATBI is an ambitiousproject involving several independentinvestigators and organizations, currentlycoordinated by the Point Reyes NationalSeashore Association. Inventories ofplankton, vascular and non-vascularplants, benthic and intertidal inverte-brates, fishes, mammals, and birds willlead to a nearly comprehensive list ofspecies in Tomales Bay. Existing and new

information will be consolidated into asingle geographic information system(GIS). Other objectives involve opportuni-ties for education, strategies for habitatrestoration, and plans for providing infor-mation to scientists and other interestedindividuals or groups. There remainsmuch to do, with a wide range of poten-tial benefits.

In the avian biodiversity report, RichStallcup and I analyzed 13 years of ACRshorebird and waterbird survey data,examined the results of numerous pub-lished and unpublished reports, and veri-fied anecdotal records of bird speciesoccurrences in Tomales Bay. The resultinglist of species, keyed by taxonomic hierar-chy, seasonality, special status categories,preferred habitats, relative abundance,and occurrence within 12 sub-areas,identifies 163 bird species known to occuror to have occurred in Tomales Bay, belowthe mean higher high-tide level (Tables 1and 2). These include 122 species thatoccur regularly or occasionally and 41species that occur very rarely, with fewerthan five documented occurrences.Species normally associated with adja-cent areas were included only if theyoccurred in habitats known to be suitablefor their use. Other species, such asBrewer’s Blackbird, which occasionallyoccurs along the shore, and YellowWarbler, which might land or even foragerarely in salt marsh Grindelia shrubs,were not included. Similarly, bird speciesthat occurred only by flying over the areaat high elevations were not included.Extremely rare species records wereincluded only if accepted by theCalifornia Bird Records Committee ofWestern Field Ornithologists.

The biodiversity report also recom-mends specific protocols for shorebirdand waterbird surveys, based on ACR’songoing (since 1989) monitoring pro-grams on Tomales Bay (see Ardeid, Spring1999 and Summer 1997). Each winter, ACRconducts three to four baywide waterbirdsurveys. Each survey requires a team of12-15 observers who work from three 17-

to 21-foot Boston Whalers or similar boatstraveling in formation along parallel 18-km transects (Figure 1). ACR also com-pletes six baywide shorebird counts eachwinter and one or more counts duringeach fall and spring migration period.Each shorebird count requires 15–20observers who simultaneously recordshorebird use among the bay’s many tidalflats and beaches. ACR field observers onTomales Bay have demonstrated a highlevel of expertise in this work, and most ofthem have been loyal to the program formany years.

Winter surveys recorded 58 species of“waterbirds” (not including shorebirdsand medium-to-large gulls). The numbersof species detected during waterbird sur-veys were greatest between Pelican Pointand Tom’s Point (50 species, Figure 1) andalong the east shore (51 species). Seasonalshorebird surveys detected 32 species,with the greatest richness of speciesoccurring at Sand Point (28 species) andWalker Creek delta (26 species).

For the biodiversity inventory, we pre-sented the bird survey results as probabil-ities of each species occurring amongyears and among surveys: by season; bay-wide and within each of 12 sub-areas; andas mean baywide abundances. Finerdetails of abundance variation and distri-

A report on the All Taxa Biodiversity Inventory of Tomales Bay

Bird Alphabet Soupby John P. Kelly

Common Loons consistently occupy all areas ofthe bay in winter, whereas Red-throated andPacific loons are most likely to occur betweenCypress and Pelican points.

Although currently rare, Clapper Rails may havebeen regular breeders in the tidal sloughs of Lagu-nitas Creek delta prior to the construction of leveesin 1946.

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visiting rarities, but also a habitat areathat supports an impressive array ofcoastal and estuarine birds. ■

Turn to pages 10–12 for the table of birdsoccurring in Tomales Bay.

References citedKelly, J. P., and R. W. Stallcup. 2003. Documented

occurrences of bird species on Tomales Bay,California, prior to January 2003, and a protocolfor future bird species inventories. A report tothe Point Reyes National Seashore and the AllTaxa Biodiversity Inventory of Tomales Bay.ACR Tech. Rpt. 89-12-6. 103 pp.

Kelly, J. P. 2001a. Distribution and abundance ofwinter shorebirds on Tomales Bay, California:implications for conservation. Western Birds 32:145–166.

Kelly, J. P. 2001b. Hydrographic correlates of winterDunlin abundance and distribution in a tem-perate estuary. Waterbirds 24: 309–322.

Kelly, J. P., and Tappen, S. L. 1998. Distribution,abundance, and implications for conservationof winter waterbirds on Tomales Bay, California.Western Birds 29: 103–120.


bution of birds have been evaluated inprevious publications (e.g., Kelly andTappen 1998; Kelly 2001a, 2001b). Overall,our work to date provides a thoroughassessment of habitat values and bird usein Tomales Bay.

To determine the optimal effort need-ed for future inventories, we examined

randomized species accumulation curves(Figure 2). These analyses suggested thatmost bird species in Tomales Bay couldbe detected by conducting 20–35 baywidewaterbird surveys over five winters and20–30 baywide counts of shorebirds overfive years, for each of the winter, fallmigration, and spring migration periods.The few additional species expected withadditional effort typically represent rarevisitors or vagrant species that do notnormally occur in the bay.

Based on species occurrences in otherareas along the Pacific Coast, RichStallcup identified five species that havenot been detected but are likely to befound in Tomales Bay in the near future:Arctic Loon, Northern Fulmar, Steller’sEider, Wilson’s Phalarope, and Sabine’sGull. These and other species most likelyto be added to the list include difficult-to-observe pelagic visitors, species withexpanding ranges, and rare species thathave been observed elsewhere along thispart of the Pacific Coast.

Over all, the avian biodiversity inven-tory of Tomales Bay reveals not only anestuary that is enriched by numerous

Figure 1. The All Taxa Biodiversity Inventory of Tomales Bay is based on ACR’s winter waterbirdcount areas (A, B, C, D); sub-areas are marked by routes of observation boats along the west shore(W), mid-bay (M), and east shore (E). Supplementary waterbird counts (circled) are conducted atWalker Creek (1), Millerton Gulch to Bivalve (2), Bivalve (3), and Inverness (4).

Figure 2. Species accumulation curves show the expect-ed (mean) number of bird species detected for each levelof effort (number of counts). Results for each level ofeffort are based on 100 random samples taken from 13years of count data from Tomales Bay, 1989–2002. Bold,dashed lines indicate the expected number of species ifsurveys are limited to five years.

Western Grebes occur throughout Tomales Bayand form stable winter rafts near Cypress Pointand Marconi Cove.

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Number of baywide counts

Winter waterbirds (n=39)

Fall shorebirds (n=20)

Spring shorebirds (n=23)

Winter shorebirds (n=20)

A A A A B B B B C C C C D D D DE M W E M W E M W E M W


Yellow-billed Loon W OB Cs X X X X X XCommon Loon W CSC,BMC OB A X X X X X X X X X X X X X X X XPacific Loon W OC,OB C X X X X X X X X X X X X X X X XRed-throated Loon W OC,OB A X X X X X X X X X X X X X X X XHorned Grebe W OB A X X X X X X X X X X X X X X X XEared Grebe W OB A X X X X X X X X X X X X X X X XRed-necked Grebe W OB C X X X X X X X X X X X X X X X XWestern Grebe W OC,OB A X X X X X X X X X X X X X X X XClark’s Grebe W OB C X X X X X X X X X X X X X X X XPied-billed Grebe R* OB,FM U X X X X X X X X X X X X X X XSooty Shearwater LM OC X X XFork-tailed Storm-Petrel LR CSC OC X X X X XAshy Storm-Petrel LR FSC,CSC,BMC OC X X XRed-footed Booby S X X XAmerican White Pelican S CSC,WL OB C X X X X X X X X X XBrown Pelican S FE,SE,BMC OC,OB C X X X X X X X X X X X X X X X XDouble-crested Cormorant R* CSC OB A X X X X X X X X X X X X X X X XBrandt’s Cormorant R OC,OB C X X X X X X X X X X X X X X XPelagic Cormorant R OC,OB C X X X X X X X X X X X X X X XMagnificent Frigatebird S A X X X X XAmerican Bittern R FSC FM X X XGreat Blue Heron R* BMC M,FM,SM C X X X X X X X X X X X X X X X XGreat Egret R* M,FM,SM C X X X X X X X X X X X X X X XSnowy Egret R FSC,CSC M,FM,SM U X X X X X X X X X X X X X X XLittle Blue Heron S M,FM,SM X X X X XBlack-crowned Night-Heron R* FSC M,FM,SM U X XTurkey Vulture R* A C X X X X X X XRoss’s Goose W FM,G Cs X X X X XEmperor Goose W FM,M,G X XSnow Goose W FM.G X X XGreater White-fronted Goose W FM,G X X XCanada Goose W* FM.G U X X X X X X X XCackling Canada Goose W FM.G X X XAleutian Canada Goose W FT FM.G X X X(Black) Brant W OB,SM A X X X X X X X X X X X X X X X X(American) Brant W OB,SM X X X X XTundra Swan W G Cs X X X XMallard W FM,SM U X X X X X X X X X X X X X X X

SPECIES SE

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Table 2. Categories and symbols used to summarize information on bird species of Tomales Bay (Table 1). Species names from: American Ornithologist’s Union.1998. Checklist of North American Birds. 7th Edition. American Ornithologist’s Union, Washington, D.C.

PREFERRED HABITAT

OB Open water of bays or estuariesOC Outer coastal water, nearshore or pelagicM Mudflat and shallowly flooded areas free of

upright vegetationFM Freshwater marsh or pondsSM SaltmarshR Rocky shoreC Cliff or other steep rocky areas lacking

vegetationB Sandy beachG Grassland, including pastures, fields,

meadows, and savannahS Shrubland in relatively dry areasr Riparian vegetation or creek channelF Forest, trees closely spaced; non-riparianW Woodland, trees widely spaced; non-riparianA Aerial; associated with strong flying species

often seen overhead

SEASONAL STATUS

W Mostly winterM Fall and or spring migrantS Mostly summerR Resident; present all yearL Local visitor from nearby habitat areas* Known to nest or have nested in the area

SPECIAL STATUS

FE Federally listed as EndangeredFT Federally listed as ThreatenedFSC Federal Special Concern species (former

Category 2 candidates)FD Federally delisted (monitoring)BMC Migratory Nongame Birds of Management

Concern, U.S. Fish and Wildlife ServiceSE State-listed as EndangeredST State-listed as ThreatenedCSC California Special Concern species, State

Department of Fish and GameWL Audubon Watch List for CaliforniaPIF Partners in Flight Watch List

RELATIVE ABUNDANCE

A Abundant; >100 individuals observed per dayin appropriate habitat and season

C Common; 10-100 individuals observed perday in appropriate habitat and season

U Uncommon; <10 individuals observed perday in appropriate habitat and season

R Rare; Observed every year but not seen dailyin appropriate habitat and season

Cs Casual; not observed every year, very unlikelyto be seen

X Extremely rare; < 5 records overall

Table 1. (Pages 10–12.) Documented bird species occurrences on Tomales Bay prior to January 2003. “X” indicates documented presence in a sub-area; actualpatterns of bird use may be broader than indicated if species occur in areas where they have not yet been detected. See Figure 1 (page 9) for sub-areas. See Table2 (below) for legend of symbols used.


Gadwall W FM,SM R X X X XNorthern Pintail W FM,SM U X X X X X X X X X X X X X XGreen-winged Teal W FM,SM R X X X X X X X X X X X X X XCinnamon Teal R* FM R X X X XBlue-winged Teal W FM X X XAmerican Wigeon W OB,FM C X X X X X X X X X X X X X X X XEurasian Wigeon W OB,FM Cs X X X XNorthern Shoveler W FM U X X X X X X X X XRedhead W OB,FM R X X X X X X X XCanvasback W FM R X X X X X X XRing-necked Duck W FM R X X X X X X XGreater Scaup W OB A X X X X X X X X X X X X X X X XLesser Scaup W OB,FM C X X X X X X X X X X X X X X X XTufted Duck W OB,FM X X X X XCommon Goldeneye W OB C X X X X X X X X X X X X X X X XBarrow’s Goldeneye W CSC,WL OB Cs X X X X X X X X X X XBufflehead W OB,FM A X X X X X X X X X X X X X X X XHarlequin Duck W FSC,CSC OB,OC Cs X X X X X XWhite-winged Scoter W OB R X X X X X X X X X X X X X X X XSurf Scoter W OC,OB A X X X X X X X X X X X X X X X XBlack Scoter W OB C X X X X X X X X X X X X X XLong-tailed Duck W OB Cs X X X X X X X X X X X X XRuddy Duck W OB,FM A X X X X X X X X X X X X X X X XHooded Merganser W FM,r Cs X X X XRed-breasted Merganser W OB C X X X X X X X X X X X X X X X XCommon Merganser W r R X X X X X X X X X X X X X XKing Eider W OC,OB X XOsprey R* CSC OB U X X X X X X X X X X X X XBald Eagle W FT,SE OB,FM X X X X X X XNorthern Harrier R* CSC G,SM,FM U X X X X X X X X XRed-shourldered Hawk LR* r,F,W URed-tailed Hawk LR* G,W,A UPeregrine Falcon W OB, M U X X X X X X X X X X X X X X XPeregrine Falcon (anatum) W FD,SE, MC OB, M X X XPrairie Falcon W CSC,WL G R X XMerlin W CSC M,A R X X X X XCommon Moorhen W* FM Cs X XAmerican Coot W* OB,FM A X X X X X X X X X X X X X X XVirginia Rail W* FM,SM U X XSora W FM R XCalifornia Clapper Rail W* FE,ST SM X X XBlack Rail R* ST,FSC,PIF FM,SM R X XYellow Rail W CSC,BMC,WL,PIF FM,SM X X XBlack-bellied Plover W M,A C X X X X X X X X X XAmerican Golden-Plover M G Cs X XPacific Golden-Plover W G Cs X XGolden-plover species WM G R X XWestern Snowy Plover W FT,CSC,BMC,PIF B,M U X X X X X XSemipalmated Plover WM M C X X X X X X X X X XKilldeer R* M,G U X X X X X X X X X XBlack Oystercatcher R* PIF,WL R R X X XAmerican Avocet W M,SM Cs X X X X X X XGreater Yellowlegs W M,SM C X X X X X X X X X XLesser Yellowlegs M FM,SM R X X X X X X X X XWillet W M,SM A X X X X X X X X X XSolitary Sandpiper M FM X XWandering Tattler W R X X X X XSpotted Sandpiper W R U X X X X X X X X XWhimbrel W M,B,SM R X X X X X X X X XLong-billed Curlew W CSC,WL,BMC,PIF M,SM R X X X X X X X XMarbled Godwit W M A X X X X X X X X X XRuddy Turnstone W R R X X X X X X X XBlack Turnstone W R U X X X X X X X X X XSurfbird M R R X X X X X XRed Knot M B,M R X X X X X X XSanderling W B,M A X X X X X X X X X XWestern Sandpiper W M A X X X X X X X X X X

A A A A B B B B C C C C D D D DE M W E M W E M W E M WSPECIES S

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Table 1 (continued).


Semipalmated Sandpiper M M X X X X XStilt Sandpiper M M X X XLeast Sandpiper W M A X X X X X X X X X XBaird’s Sandpiper M FM,M R X X X X X XPectoral Sandpiper M FM X X XDunlin W M A X X X X X X X X X XRuff W SM,FM X X XShort-billed Dowitcher M M,SM C X X X X X X X X XLong-billed Dowitcher W M,FM,SM C X X X X X X X XDowitcher species WM M,FM,SM C X X X X X X X X X XWilson’s Snipe W G U X X X X X X X X XRed-necked Phalarope M FM,OB R X X X X X X X X XRed Phalarope LM OC, OB Cs X X X X X X X X X X X X X X X XParasitic Jaeger M OC,OB U X X X X X X X XFranklin’s Gull M B,M,OB X X X X XLaughing Gull M CSC B,M,OB X X XBlack-headed Gull M OB X X X X XLittle Gull M OB X X XBonaparte’s Gull M OB R X X X X X X X X X X X XHeermann’s Gull S OB C X X X X X X X X X X X X X X X XMew Gull W OB U X X X X X X X X X X XRing-billed Gull R B,M,OB C X X X X X X X X X X X X X X X XCalifornia Gull W CSC B,M,OB A X X X X X X X X X X X X X X X XHerring Gull W B,M,OB U X X X X X X X X X XThayer’s Gull W B,M,OB R X X X X X XWestern Gull R* B,M,OB A X X X X X X X X X X X X X X X XGlaucous-winged Gull W B,M,OB A X X X X X X X X X X X X X X X XGlaucous Gull W B,M,OB X X X X XBlack-legged Kittiwake LW OC X X X XCaspian Tern S B,M,OB C X X X X X X X XRoyal Tern W B,OB XElegant Tern S FSC,CSC,BMC OB C X X X X X X X X XCommon Tern M OB Cs X X X X X X XArctic Tern LM OC X X XForster’s Tern R WL OB U X X X X X X X X X X X X X X X XCalifornia Least Tern M FE,SE,BMC OB X X XBlack Tern M FSC,CSC,BMC FM,SM,G X XBlack Skimmer S CSC,WL,BMC,PIF OB X X XCommon Murre LR OC,OB R X X X X X X X X X X XPigeon Guillemot LS OC X X XMarbled Murrelet LR FT,SE,BMC OC X XRhinoceros Auklet LR CSC OC X X X XCassin’s Auklet LR OC X X XBarn Owl LR* G,W,r R X XGreat-horned Owl LR* CSC,WL,BMC,PIF G,W,r,F R X X X XShort-eared Owl W FSC,CSC,WL,BMC FM,SM,G X X XBelted Kingfisher R* C,OB U X X X X X X X X X X X XBlack Phoebe R* F,M,r U X XAmerican Crow R* G,r,W C X X X XCommon Raven R* G,W C X X X X X X X X X XHorned Lark W* CSC G R X XMarsh Wren R* FM,SM U X X X XAmerican Pipit W G,SM,FM,B U X X X X X XLoggerhead Shrike W FSC,CSC,BMC,WL G,W X XNorthern Shrike W G,W X XSaltmarsh Common Yellowthroat R* FSC,CSC, FM, SM U X X X X X X XSavannah Sparrow R G,SM C X X X X X X X X X X XNelson’s Sharp-tailed Sparrow W SM X XSong Sparrow R r,FM,S C X X X X X X X X X X XSwamp Sparrow W FM R X X X XLincoln’s Sparrow W S,r,G U X XGolden-crowned Sparrow W S,G C X X X X X X X XWhite-crowned Sparrow R* S,G C X X X X X X X XWestern Meadowlark W* G,SM U X X X X X

A A A A B B B B C C C C D D D DE M W E M W E M W E M WSPECIES S

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SUB-AREAS

Table 1 (continued).


Research at Audubon Canyon Ranchmay be more valuable than youthink. As human impacts on nature

continue to expand and intensify aroundus, visiting scientists at ACR recognize theincreasing value of our sanctuaries asundisturbed, natural laboratories. Theirinvestigations result in numerous contri-butions to ecological science, often withstrong conservation applications, andtheir work provides us with sophisticatedinformation about the ecology of oursanctuaries. Because of limits on thenumber of studies we can host withoutaltering the natural character of our sanc-tuaries, we have been able to select fromproposed projects the ones most likely tomake a difference in conservation, locallyas well as globally.

For example, the occurrence on ACRlands of Sudden Oak Death (SOD), a dis-ease resulting from a newly describedpathogenic organism, Phytophthoraramorum, provides a unique opportunityto study its effects on oak woodlandecosystems (see Ardeid 2002). At BouveriePreserve and several other locationsaround the San Francisco Bay area, DonDahlsten, Kyle Apigian, and DavidRowney (UC Berkeley) are investigating

SOD impacts on the nesting success, diet,foraging behavior, and habitat use of cavi-ty-nesting birds. They are also using livetraps to monitor the effects on small

mammals, and coverboards to monitorreptiles and amphib-ians. Ultimately, theyplan to collaboratewith Barbara Allen-Diaz and Letty Brown(UC Berkeley), whowill use vegetationdata collected on thesame plots to under-stand how SOD-induced changes inforest structure willaffect the demogra-phy and functionalresponses of wildlifein California.

Cheryl Briggs,Martha Hoopes andJohn Latto (UC

Berkeley) are studying metapopulations(groups of populations) of a gall-formingmidge (Rhopalomyia californica) and asuite of parasitoid wasps that attack thismidge. In particular, they are measuringthe effects of dispersal and habitat struc-ture in coyote brush (Baccharis pilularis)on the population dynamics of thesespecies, with general implications abouthow species coexist. Dissections of morethan 6,000 galls revealed outbreaks ofmidges to extremely high densities atBolinas Lagoon Preserve (BLP). AtCypress Grove Preserve (CGP), parasitoiddensities varied more from place to placeand seemed to mimic midge densitiesbetter, allowing greater control.

As in most ecological investigations,numerous factors must be examined toassess the underlying processes affectingmidge populations. Therefore, VanessaSchmidt (UC Berkeley) and MarthaHoopes are further examining microenvi-ronmental influences. By experimentallyplacing midges in mesh sleeves on

Visiting investigators on ACR lands

The Other Scientific Agenda

by John P. Kelly

Continued on page 14

ACR lands provide natural laboratories where researchers from other institutions may conduct ecologicalfield studies. Pictured here: Shelene Poetker (left) and Chris DiVittorio sample plants and count seeds in astudy of coastal prairie at Toms Point (see pages 15–16).

Martha Hoopes, Cheryl Briggs, and John Latto (UC Berkeley) used tent-like exclosures in a study of insect populations at Bolinas Lagoon andCypress Grove preserves, to examine the importance of dispersal and iso-lation in the persistence of fragmented populations.

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branches in caged and uncaged environ-ments, they found that season, plantquality (stem growth), and wind had largeeffects on successful gall and midgedevelopment. Currently, they are investi-gating these seasonal influences by set-ting up growth chambers to test theeffects of temperature and water. Together,these studies of midge and parasitoidpopulations will test general principlesused in the conservation of isolated pop-ulations of endangered species and in thecontrol of ecological pests.

Conservation agencies commonly usehabitat relationship models to determinewhether areas proposed for increasedhuman use are suitable for particularnative species. Jennifer Shulzitski (USGS-Golden Gate Field Station) is conductinga regional study to test the ability of vege-tation data and habitat maps to predictwildlife distributions, for use with existingwildlife habitat relationship models. Shesurveyed for mammals, amphibians, andreptiles within 15-meter, circular plots,using sooted track plates, Sherman livetraps, pitfall traps, and cover boards. AtBLP, she detected two species of amphib-ians and nine of mammals in habitatdominated by California bay laurel; oneamphibian and nine mammals in coastlive oak habitat; and one amphibian, onereptile, and eight mammals in coyotebrush. During point counts to surveybirds, she detected 35 species inCalifornia bay, 25 in coast live oak, and 31in coyote brush.

In other bird research, longtime ACRvolunteer Ken Burton initiated a bird-banding station this spring in LivermoreMarsh at CGP. With the help of DeniseJones of The Institute for Bird Populations(IBP) and ACR’s Michael Parkes, the sta-tion proved to be very productive, with 54

captures of 46 individuals of 13 species insix hours of operation. This station will bepart of the Monitoring Avian Productivityand Survivorship (MAPS) Program coor-dinated by IBP. Data collected will be ana-lyzed along with those from other MAPSstations in the region to monitor regionaltrends in adult population size, produc-tivity, survivorship, and recruitment.

In coastal areas such as Tomales Bayand Bodega Harbor, eelgrass (Zosteramarina) provides valuable ecosystemservices, such as enhancing primary pro-duction, providing habitat for ecologicallyand economically important species, andbuffering against erosion. Randall Hughes(UC Davis) is measuring genetic diversity,shoot density, epiphyte biomass, andinvertebrate diversity in eelgrass atCypress Grove Preserve and at eight otherlocations in Tomales Bay and BodegaHarbor. Using these data, he plans toevaluate the importance of genetic diver-sity to the ecosystem services eelgrassprovides.

Tidelands and salt marshesLand use practices such as grazing can

substantially increase the input of nitro-gen as runoff into estuaries. Bibit Traut(UC Davis) recently completed her PhDon the effects of nitrogen addition on thestructure and dynamics of salt marsh veg-etation in the Point Reyes area. In a fieldexperiment at ACR’s Walker Creek Marsh,she found that nitrogen addition did notresult in the predicted increase in plantproductivity and competitive exclusion ofother species by salt grass (Distichlis spi-cata). Instead, nitrogen addition led togreater overall biomass and tissue nitro-gen, especially in Triglochin concinna andJaumea carnosa.

Plants can have important roles in reg-ulating ecosystems. For example, somespecies can actively alter nutrient avail-

ability and species distributions.Understanding the roles of influentialplants is essential if we are to predict theconsequences of species losses or gainsassociated with human impacts orrestoration efforts. At ACR’s Toms Point,Brenda Grewel (UC Davis, currently atUniv. South Bohemia, Czech Republic) isstudying the potentially important role ofparasitic plants such as the rare, but local-ly abundant, Point Reyes bird’s beak(Cordylanthus maritimus subsp. palus-tris). Her research asks whether the para-site-host plant physiological link amelio-rates stresses imposed by tidal inundationand salinity. Experimental results suggestthat the parasite-host interaction modi-fies sediment (biogeochemical) condi-tions, improving aeration and salinity,and enhances community diversity.

The recovery of rare species oftenrequires a detailed knowledge of the lifehistory characteristics of target popula-tions. Tod Wilms (UC Berkeley) may havefound such important information in therare salt marsh annual, Point Reyes bird’sbeak: certain populations of this species

Swainson’s Thrush (pictured) and Song Sparrowwere the most frequent captures at the newlyestablished MAPS station in Livermore Marsh.

Elizabeth Brusati (UC Davis) is measuring the responses of salt marsh invertebrates, such as the nativeamphipod, Corophium (left), and the introduced worm, Streblospio benedicti (right), to invasions by non-native cordgrass.

The rare, parasitic salt marsh plant, Point Reyesbird’s beak, is the subject of two studies by visitinginvestigators on ACR’s Tomales Bay properties.

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may employ different reproductivemodes. Two of the inner coastal popula-tions maintain a floral structure with spa-tial separation between anthers and stig-ma. The outer coastal populations stud-ied do not maintain this separation offemale and male function, are apparentlynot visited by pollinators, and may repro-duce entirely by “selfing.” To understandthese differences, Tod plans to examinethe relationship between reproductivemode and genetic variation among thesepopulations.

Invasions by influential, non-nativespecies can have devastating conse-quences on native ecosystems. ElizabethBrusati (UC Davis) is studying themacroinvertebrates in Pacific cordgrass(Spartina foliosa) marshes at ACR’s TomsPoint and Shields Marsh on Tomales Bay,and in San Francisco Bay marshes invad-ed by non-native East Coast cordgrass(Spartina alterniflora). Understandingthe invertebrates in these systems isimportant because they are the food forthousands of migratory shorebirds, andpotential new invasions of non-nativecordgrass threaten other West Coast estu-

aries. So far, Elizabeth has found higherdensities of small invertebrates in Pacificcordgrass marshes than in the invadedmarshes in San Francisco Bay. She is alsoconducting chemical analyses of inverte-brates and plants to determine the rela-tive importance of native cordgrass, pick-leweed, and East Coast cordgrass tomarsh food webs.

Ecological restoration andmonitoring

The National Park Service is currentlyplanning a wetlands restorationproject for Giacomini Marsh, a large

diked area at the southern end of TomalesBay. Through reduction of contaminants,the project could augment other efforts toimprove water quality in Tomales Bay,which has been declared “impaired” forsediment, nutrients, pathogens, and mer-cury by the San Francisco Regional WaterQuality Control Board. Lorraine Parsonsand her coworkers at the Point ReyesNational Seashore are planning to con-duct monitoring before and after restora-tion is implemented. A long-term moni-toring program will begin in October2003, but they have already initiatedwater quality monitoring in the projectarea and in selected reference wetlands,including ACR’s Walker Creek Marsh.

Perhaps the most ambitious project onACR lands is being conducted by the“Pacific Estuarine Ecosystem IndicatorResearch (PEEIR) Consortium.” This mul-tidisciplinary group, led by SusanAnderson, Steven Morgan, Gary Cherr,and Roger Nisbet (UC Bodega Marine Lab

and UC Santa Barbara), includes 30 uni-versity scientists and non-profit partnersfrom The Bay Institute and San FranciscoEstuary Institute. Their goal is to developa suite of ecological indicators to rapidlyassess the integrity and sustainability ofWest Coast estuaries. The study sites,carefully selected in northern and south-ern California, include ACR’s Walker Creekand Toms Point properties in TomalesBay, Stege Marsh and China Camp in SanFrancisco Bay, Morro Bay, CarpinteriaMarsh, and Mugu Lagoon. The indicatorswill measure impacts across levels of bio-logical organization, trophic structure, lifestage, time, and space. They are beingdeveloped by contrasting conditions atreference and impacted sites, and by fol-lowing nutrient gradients at all sites andtoxic contaminant gradients at three sites(Stege Marsh, Carpinteria Marsh, andMugu Lagoon). For more information onthis project, see http://www.bml.ucdavis.edu/peeir.

Coastal prairie

In their work at ACR’s Toms Point onTomales Bay, Jeffrey Corbin and CarlaD’Antonio (UC Berkeley) have led a

series of investigations on the ecology ofcoastal prairie ecosystems. In one study,they examined the competitiveness ofnon-native annual grasses to test whetherthe 19th-century introduction of exoticpropagules into California grasslands wassufficient to shift community composi-tion from native perennial to exotic annu-al grasses. They compared the above-ground productivity of native species

Figure 1. Mean productivity (± 1 SE) of nativeperennial bunchgrasses and exotic annual grassesfrom 1998-2002. Annual competitors reducednative growth in the first three years, but by thefourth year, annuals had no effect on natives. Aster-isks indicate significant differences between “Nocompetitor” and “With competitor” treatments.

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View of Giacomini Marsh from Railroad Point, near the mouth of Lagunitas Creek, where the National ParkService is initiating a monitoring program to measure changes resulting from the planned restoration oftidal wetlands.

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alone to native species competing withexotics, and exotic species alone to exoticspecies competing with natives. Over thecourse of the five-year experiment, nativegrasses have become increasingly domi-nant in the mixed-assemblage plots andhave significantly reduced the productivi-ty of exotic annual grasses since the sec-ond growing season (Figure 1). Given therelative competitiveness of the natives, itis unlikely that the introduction of exoticannual grass propagules alone, withoutchanges in land use or climate, was suffi-cient to convert coastal prairie grasslands.

Sally Reynolds (UC Berkeley) collabo-rated with Jeff and Carla to examine thegermination rates of native and exotic,annual and perennial grass seeds as afunction of varying litter cover and tem-perature. Non-native species germinatedat consistently higher rates than nativespecies. Most non-natives tolerated arange of temperatures, and their rapidgermination after wet-up may explaintheir expansive distribution throughoutCalifornia. However, rapid germinationmay be only part of the story. ChristopherDiVittorio (UC Berkeley) measured seedrain, seed banks, and colonization of arti-ficial gopher mounds and determinedthat early flowering and a ubiquitouspresence in soil seed banks may allowexotic species to usurp new sites quicklybefore native species can disperse.

In other experimental work, Jeff andCarla have found that nitrogen cyclingrates are faster in coastal prairie plotsdominated by non-native annual grassesthan in plots dominated by either nativeor non-native perennial grasses. Theannual-dominated plots were also lessable to retain nitrogen. From this work,they have concluded that the invasion byexotic annual grasses, and subsequentinvasion by exotic perennial grasses, haveeach influenced the cycling and retentionof nitrogen in California grasslands.

During the last decade, coastal prairiehabitats in northern California have suf-fered massive invasions by non-nativeperennial grasses. Using stable isotopes ofhydrogen and oxygen, Jeff, Carla,Meredith Thomsen, and Todd Dawson(UC Berkeley) found that 16–66% of thewater in perennial grasses during sum-mer at Toms Point (and three othercoastal sites) came from fog. Thus, theuse of water from coastal fog may providea competitive advantage to invasiveperennial grasses.

One of the most abundant and wide-spread of California’s native perennialbunchgrasses, Nassella pulchra, receives

substantial water from coastal fog.However, inland N. pulchra popu-lations are unlikely to receive anymoisture during summer. Suchdifferences may contribute to dif-ferences in root activity. Jeff usedstable isotope analyses to deter-mine that zones of water uptakeat inland sites, at ACR’s BouveriePreserve and Jepson Prairie, weredeeper than at Toms Point. He isplanning to build on these resultsto determine whether differencesin water use arise from local adap-tation or, alternatively, phenotypicplasticity.

In other experiments at TomsPoint, Tasha Teutsch, MonicaCundiff, Vannessa Schmidt, andJeff Corbin (UC Berkeley) foundthat soil water was less availablein “neighborhoods” invaded byexotic grasses than in pure nativestands. But, surprisingly, nativegrasses were less water stressedwhen grown with exotics. Thesepreliminary results suggest that the inva-sion of California grasslands has alteredwater availability as well as the water usestrategies of native grasses.

In 1999, Carla D’Antonio establishedpermanent vegetation transects at TomsPoint. Preliminary results from these tran-sects suggest that ACR efforts to manuallyremove aggressive, non-native perennialgrasses, such as orchard grass (Dactylisglomeratus) and velvet grass (Holcuslanatus), are helping to maintain thenative coastal prairie!

The ecosystem effects of changes inCalifornia’s coastal grasslands are mostlyunknown. However, Natalie Robinson(UC Berkeley) and Jeff Corbin are analyz-ing data from Toms Point that suggesthigher diversity of arthropods (insects,spiders, and other invertebrates) in areasdominated by native and exotic perennialgrasses than in areas dominated by exoticannual grasses. Much more work is need-ed to understand how coastal ecosystemsare affected by changes in vegetation.

Natural areas in human land-scapes

ACR’s Bouverie Preserve is oftenused either as a natural controlarea in projects that include other

sites or as a key component of the largerecological landscape. These uses includestudies on the health of riparian wetlandsin the Sonoma Creek watershed, byCaitlin Cornwall and David Luther(Sonoma Ecology Center); bird communi-

ties in oak-vineyard landscapes, by EmilyHeaton, Mark Reynolds, and GretchenLeBuhn (UC Berkeley); effects of land-scape change on native bees and pollina-tion of native plants in Napa and Sonomacounties, by Gretchen LeBuhn (CSU SanFrancisco); impacts of butterfly gardenson pipevine swallowtail populations, byJacqueline Levy (CSU San Francisco); andthermal monitoring in the Sonoma Creekwatershed, by Wendy Losee (SonomaEcology Center).

Additional work on ACR’s Tomales Bayproperties include studies of environ-mental stressors and mortality of Pacificoysters, by Fred Griffin, Gary Cherr, andothers (Bodega Marine Lab); a survey forthe federally endangered tidewater goby(Eucyclogobius newberryi), by DarrenFong (GGNRA); and surveys of BlackBrant in Tomales Bay, Drakes Estero andBodega Harbor, by Rod Hug (Santa Rosa).

It is exciting that so much research isgoing on at ACR. Visiting scientists notonly help ACR to understand the livingsystems we protect, but they are makingimportant contributions to conservationbiology on a global scale. When combinedwith scientific contributions by ACR staffand collaborators, these projects illustratethe broad perspective on conservationneeded to ensure the long-term health ofour sanctuaries. ■

Fog may be an important factor in the invasion of coastalprairie by non-native perennial grasses.

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North Bay counties heronand egret project ◗ Annualmonitoring of reproductiveactivities at all known heronand egret colonies in fivenorthern Bay Area countiesbegan in 1990. The data areused to examine regionalpatterns of reproductiveperformance, disturbance,habitat use, seasonal timing,and spatial relationships amongheronries.

Picher Canyon heron andegret project ◗ The fates ofall nesting attempts at ACR’sPicher Canyon heronry aremonitored, and reproductivesuccess is analyzed annually.Field procedures are based onmethods developed by HelenPratt, who initiated the projectin 1967 and published severalpapers on heron and egretnesting biology.

Livermore Marsh ◗ AsACR’s Livermore Marshtransforms from a freshwatersystem into a tidal salt marsh,we are studying the relation-ship between increasing tidalprism and marsh channeltopography. The results arebeing compared with datafrom mature referencemarshes and will contribute tofuture restoration designs. Theresults will also contribute tostudies of changing bird useand vegetation in the marsh.

Newt population study ◗Annual newt surveys havebeen conducted along theStuart Creek trail at BouveriePreserve since 1987. Theresults track annual andintraseasonal abundance, andsize/age and spatialdistributions along the creek.

Shorebirds ◗ Since 1989, wehave conducted annual bay-wide shorebird censuses onTomales Bay. The data areused to investigate winterpopulation patterns of shore-birds, local habitat values, andconservation implications.Other associated work hasinvolves the effects of winterstorms and food availability onenergy balance and habitatuse.

In progress:project updates

Tomales Bay waterbirdsurvey ◗ Since 1989-90,teams of 12-15 observers haveconducted winter waterbirdcensuses from survey boatson Tomales Bay. The resultsprovide information on habitatvalues and conservation needsof 51 species, totaling up to25,000 birds. Publicationsgenerated from this workhighlight status andconservation concerns forwaterbirds on Tomales Bay.

Predation by ravens inheron and egret colonies◗ We are observing nestingravens in Marin County andmeasuring their predatorybehaviors at heron and egretnesting colonies, with anemphasis on heronries atACR’s Picher Canyon andMarin Islands National WildlifeRefuge. Radio telemetry andbehavioral studies focus onevaluating home rangevariation, behaviors atheronries, and diurnalmovement patterns. A roadsurvey conducted throughoutthe San Francisco Bay arearevealed concentrations ofravens in some urban/suburbanareas and along the outercoast.

Plant species inventory ◗Resident biologists maintaininventories of plant speciesknown to occur at Bouverieand Bolinas Lagoon preserves.Grant Fletcher has establisheda database of shoreline plantspecies on Tomales Bay.

Annual Cordylanthussurvey ◗ This projectcontinues earlier fieldinvestigations on habitat andspatial relationships amongpatches of Point Reyes bird’sbeak, Cordylanthus maritimuspalustris, in Tomales Baymarshes (Kelly and Fletcher1994, Madrono 41: 316–327).The goal is to further addressquestions about long-termstability and biogeographicrelationships among discretepatches on Tomales Bay.

Oak restoration ◗ Plantingof native oaks at BouveriePreserve was conducted withthe help of school children.Annual monitoring involvedmeasurements of oak saplingsurvivorship and vigor as wellas breeding bird censuses (seeArdeid 2002).

Cape ivy control ◗ Workconducted by Len Blumin hasproven that manual removal ofnon-native cape ivy cansuccessfully restore riparianvegetation in ACR’s VolunteerCanyon. Continued vigilance inweeded areas has beenimportant, to combat resproutsof black nightshade, Vinca, andJapanese hedge parsley.

Eucalyptus removal atBouverie and BolinasLagoon preserves ◗Eucalyptus at Pike CountyGulch of Bolinas LagoonPreserve and along theHighway 12 border of BouveriePreserve are being cut andremoved with incrementalannual efforts. Stumps andresprouts will be treated bymethods developed in anassociated investigation byDan Gluesenkamp.

Eucalyptus resproutcontrol ◗ An experiment isbeing conducted to determinethe optimal method forcontrolling eucalyptusresprouts. Dan Gluesenkamp istesting the relative effective-ness of cutting, use of theherbicide Rodeo (glyphosate),and grinding stumps, topermanently kill cut eucalyptustrees in the lower field atBouverie Preserve.

Bluebird boxes ◗ TonyGilbert recently establishedWestern Bluebird nest boxesat Cypress Grove Preserve.Soon after installation, a pair ofTree Swallows moved into oneof the boxes. Tony is monitor-ing the boxes and plans toinstall additional boxes nearby,if necessary, to encourage theiruse by nesting bluebirds.

Wood Duck boxes ◗ In aneffort to supplement WoodDuck habitat in west Marin,Rich Stallcup has establishedand monitors 40 nest boxes inthe Olema Valley, includingnine along Bear Valley Creek atACR’s Olema Marsh. Theseboxes have been fledgingconsiderable numbers of WoodDucks since 1998.

Experimental assessmentof Wild Turkey impacts ◗Dan Gluesenkamp is measur-ing the effects of foraging bynon-native Wild Turkeys onvegetation structure andcomposition and the compo-sition of invertebrates andherpetofauna at BouveriePreserve. He is also measuringthe consumption of specificfood items by turkeys. Resultswill be used to evaluateecological impacts of WildTurkeys in forest ecosystems,and to substantiate efforts tocontrol the impacts ofintroduced turkeys in westernlandscapes.

Annual surveys andremoval of non-nativecordgrass ◗ Katie Etienne ishelping to coordinate annualsurveys of tidelands in TomalesBay, Drakes Estero, andBolinas Lagoon to preventinvasion by non-native Spartinaspecies (and their hybrids) withour native Spartina foliosa. Theproject is a collaboration withthe San Francisco InvasiveSpartina Project (CaliforniaCoastal Conservancy), PointReyes National Seashore,Golden Gate NationalRecreation Area, and localpartners who share a commit-ment to proactive stewardshipof natural areas in west MarinCounty (See Ardeid 2002).


Ardeid (Ar-DEE-id), n., refers to

any member of the family

Ardeidae, which includes herons,

egrets, and bitterns.

The Ardeid is published annually by Audubon Canyon Ranch as an offering to field

observers, volunteers, and supporters of ACR Research and Resource Management.

To receive The Ardeid, please call or write to the Cypress Grove Research Center.

Subscriptions are available free of charge; however, contributions are gratefully

accepted. ©2003 Audubon Canyon Ranch. Printed on recycled paper.

Managing Editor, John Kelly. Layout design by Claire Peaslee.

AUDUBON CANYON RANCH IS A SYSTEM OF WILDLIFE SANCTUARIES

AND CENTERS FOR NATURE EDUCATION

BOLINAS LAGOON PRESERVE • CYPRESS GROVE RESEARCH CENTER • BOUVERIE PRESERVE

the

Ardeid

Research

and Resource

Management at

Audubon Canyon Ranch

Audubon Canyon Ranch

4900 Shoreline Hwy., Stinson Beach, CA 94970

Cypress Grove Research CenterP.O. Box 808Marshall, CA 94940

(415) 663-8203

Nonprofit Org.U.S. Postage

PAIDPermit No. 2

Stinson Beach, CA

Marin Islands monitoring see page 1

Black-crowned Night-Herons are often the firstspecies to flee when mixed heronries are

disturbed by humans or predators.

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Documents

Research and Resource Management at Audubon … Kelly, PhD, Director, Research & Resource Management Rebecca Anderson-Jones, Bouverie Preserve Katie Etienne, Research Coordinator