1

U.S. Fish & Wildlife Service

RAPTOR MONITORING IN THE UPPER TANANA VALLEY,

GAME MANAGEMENT UNIT 12, ALASKA, 2004-2005

Henry K. Timm, W. N. Johnson

Progress Report 01-06

November 2006

Dan Small

Tetlin National Wildlife Refuge

P.O. Box 779 Tok, Alaska 99780

2The mission of the National Wildlife Refuge System is to administer a national network of lands and

waters for the conservation, management and where appropriate, restoration of the fish, wildlife, and

plant resources and their habitats within the United States for the benefit of present and future

generations of Americans.

Suggested Citation:

Timm, H. K., and W. N. Johnson. 2006. Raptor monitoring in the Upper Tanana Valley, Game

Management Unit 12, Alaska, 2004-2005. Progress Report 01-06. Region 7, U.S. Fish and Wildlife

Service, Alaska.

Disclaimer: The use of trade names of commercial products in this report does not constitute

endorsement or recommendation for use by the federal government.

3TABLE OF CONTENTS

ABSTRACT......................................................................................................................................... 4 BACKGROUND ................................................................................................................................. 5 OBJECTIVES ..................................................................................................................................... 7 STUDY AREA .................................................................................................................................... 8 METHODS .......................................................................................................................................... 8 RESULTS AND DISCUSSION ....................................................................................................... 11

Bald Eagle...................................................................................................................................... 11 Osprey ............................................................................................................................................ 13 American Peregrine Falcon ......................................................................................................... 14 Owls................................................................................................................................................ 17 Other Raptors ............................................................................................................................... 18

ACKNOWLEDGMENTS ................................................................................................................ 19 LITERATURE CITED .................................................................................................................... 19

Table 1. Status and abundance of raptors known to occur in GMU 12, Alaska1. .......................... 25 Table 2. Bald eagle and osprey surveys conducted by agencies and contractors in GMU 12, Alaska, 1983-2005.......................................................................................................................... 26 Table 3. Peregrine falcon surveys conducted by agencies and contractors in GMU 12, Alaska, 1979-2005. ...................................................................................................................................... 27 Table 4. Summary of trends in bald eagle territory status in Game Management Unit 12, Alaska, 1991-2005. ...................................................................................................................................... 28 Table 5. Summary of trends in osprey territory status in Game Management Unit 12, Alaska, 1991-2005. ...................................................................................................................................... 29 Table 6. Summary of trends in peregrine falcon territory status in Game Management Unit 12, Alaska, 1991-2005.......................................................................................................................... 30 Table 7. Nesting success, productivity and mean brood size of peregrine falcon populations from selected studies in eastern interior Alaska, 2004, 2005 and long term means................................ 31 Figure 1. Raptor survey area in the Upper Tanana Valley (GMU 12), Alaska. ............................ 32 Figure 2. U.S. Fish and Wildlife Service Raptor Observation Record Card. ................................ 33 Figure 3. Bald eagle nesting occupancy, success and productivity in the Upper Tanana Valley (GMU 12), Alaska, 1991-2005....................................................................................................... 34 Figure 4. Osprey nesting occupancy, success and productivity in the Upper Tanana Valley (GMU 12), Alaska, 1991-2005................................................................................................................... 35 Figure 5. Peregrine falcon nesting occupancy, success and productivity in the Upper Tanana Valley (GMU 12), Alaska, 1991-2005. .......................................................................................... 36

4ABSTRACT

Raptor occupancy and productivity surveys were completed within Alaska Game Management Unit

(GMU) 12 in the Upper Tanana Valley between 20 May and 29 July 2004, and 14 May and 26 July

2005. In 2004, we made 269 observations at 158 nest sites in 121 raptor nesting territories. In 2005,

we made 280 observations at 154 nest sites in 114 raptor nesting territories. Bald eagle (Haliaeetus

leucocephalus), osprey (Pandion haliaetus) and American peregrine falcon (Falco peregrinus anatum)

nests accounted for 81% of the 485 raptor nests documented since 1961. Most raptor nests were

located along rivers and wetlands in the Upper Tanana Valley within the habitats that sustain their

prey.

In 2004, we recorded the poorest breeding season for bald eagles since 1991; high temperatures early

in the summer, smoky atmospheric conditions during midsummer and survey timing may have been

contributing factors. Bald eagle nest occupancy (56.5%) was well below the 1991-2003 long-term

average of 68.0% ± 3.64 (mean ± 95% C.I.). Nest success (21.9%) and productivity (0.22

young/occupied nest) were both the lowest recorded for the same period and well below the respective

13-yr mean values ( x = 55.16% ± 5.94; x = 0.70 ± 0.08). In 2005, bald eagle nest success improved to

51.5%, however occupancy (57.6%) and productivity (0.55) remained below long-term means.

In contrast to bald eagles, osprey had an excellent breeding season in 2004. Although osprey nest

occupancy (73.5%) was comparable to the 1991-2003 mean ( x = 75.96% ± 4.08), success (70.0%) and

productivity (1.45 young/occupied nest) were both well above the respective 13-yr means ( x = 55.85%

± 6.49; x = 1.02 ± 0.17). In 2005, osprey nest occupancy (77.4%), success (62.5%) and productivity

(1.13) were all within expected ranges.

Peregrine falcon nest occupancy (100%) in 2004 was higher than the 1991-2003 mean ( x = 88.07% ±

7.43). However, success (78.6%) and productivity (1.93 young/occupied nest) were both lower than

expected ( x = 88.33% ± 8.36; x = 2.35 ± 0.42). In 2005, falcon nest occupancy (87.5%), success

(81.8%) and productivity (2.00) were all within expected ranges. The number of known falcon

territories (n=20) has more than doubled in GMU 12 since 1999.

5 BACKGROUND

One of the established purposes for Tetlin National Wildlife Refuge (Refuge) is "to conserve fish and

wildlife populations and habitats in their natural diversity including but not limited to, waterfowl,

raptors and other migratory birds..." Predators at the top of the ecological web are indicators of

environmental health because their existence and welfare depend on the levels below them (Cade et al.

1988, USFWS 2001). Nineteen species of raptors occur in GMU 12 (Table 1; Figure 1). Raptor

monitoring efforts have emphasized such indicator species whose nesting sites are relatively easy to

locate. These include American peregrine falcon, bald eagle, and osprey. Falcons are closely

monitored due to their prior classification under the Endangered Species Act of 1973. After removal

from the list of endangered species in August 1999, it was recommended that the Tanana River falcon

population be monitored for at least 5 years following delisting (USFWS 1982, Wright and Bente

1998). Special attention is given to bald eagles and golden eagles (Aquila chrysaetos) because they are

protected under the Bald Eagle Protection Act as amended in 1962 (USFWS 2001). Bald eagles and

osprey are important because of their close association with aquatic ecosystems.

The first scientific documentation of raptors in the Upper Tanana Valley and GMU 12 were made in

1921 by Olaus Murie (unpublished field notes, Rasmuson Library, University of Alaska 1921) when he

noted 5 pairs of nesting peregrine falcons and numerous red-tailed hawks along the Tanana River

between Tanacross and Shaw Creek. Raptors have been periodically surveyed in GMU 12 since 1961

(Roseneau et al. 1981, Schempf 1983). Peregrine falcons along the Tanana River from the Alaska

Highway bridge to Nenana were surveyed in 1968 and then annually beginning in 1970 (Haugh 1976,

Wright and Bente 1998, Shook et al. 2003). Raptor surveys were conducted along the proposed

Northwest Alaskan Pipeline Company pipeline route adjacent to the Alaska Highway in 1977 and

1979-1981 (Kessel 1978; Roseneau and Bente 1979, 1981; Ritchie and Curatolo 1981; Roseneau et al.

1981). Different organizations have conducted annual surveys for raptors in GMU 12 since 1983;

however these efforts have not consistently monitored the same species or the same areas (Timm et al.

1993, 2004). A histogram is provided for bald eagle and osprey surveys from 1983 to 2005 (Table 2)

and another for peregrine falcon surveys from 1979 to 2005 (Table 3). Below is a brief summary of

these efforts.

6In 1983 the Alaska Department of Fish and Game (ADF&G) began osprey productivity surveys on

several large lakes on Tetlin Corporation lands and the northern portion of Tetlin Refuge (Hughes

1987; Table 2, Figure 1). Annual occupancy surveys for osprey and bald eagles were added in 1986

(Hughes and Wright 1990). During productivity surveys, ADF&G also banded osprey and occasional

bald eagle nestlings, and collected addled eggs and prey remains. Refuge staff began assisting with

these efforts in 1990, and assumed responsibility for raptor monitoring on Tetlin Corporation lands in

1994. Additionally a Challenge Cost-share Agreement was signed by Tetlin Refuge, ADF&G, Alaska

Gateway School District and the Tetlin Village Council in 1993 and continued for most years through

2000. The grant provided funding to teach osprey biology to students from local schools and take

them into the field to observe and assist in the osprey banding operations.

From 1979 to 2003, the Tanana River from Tanacross to Fairbanks was surveyed annually for

peregrine falcon occupancy and productivity by the USFWS Endangered Species office in Fairbanks

(1979-1991), ADF&G (1992-1996), and Alaska Biological Research, Inc. (ABR, Inc.; 1996-2003);

(Wright and Bente 1998, Shook et al. 2003; Table 3, Figure 1). Coverage was expanded to begin at the

Alaska Highway bridge east of Tok in 1985. Peregrine nestlings were banded and addled eggs and

prey remains collected; bald eagle observations were also recorded. From 1989 to 1994, the USFWS

Endangered Species office in Fairbanks conducted aerial nest occupancy surveys along the Tanana

River, primarily for bald eagles. In addition, raptor nests were located and monitored from 1987 to

1989 in the Tok area (Cathedral Rapids to the Alaska Highway Bridge) for the Over-the-Horizon

Backscatter Radar Avian Field Survey Program (Alaska Biological Research 1987; Cooper et al. 1988,

1990).

Raptor monitoring efforts by refuge staff began with spring aerial nest platform surveys to locate new

raptor nests along waterways in 1984-1987, and 1990 (Table 2). In 1987 two technicians spent 11

weeks from mid-May until late July searching for raptor nests on the refuge. Annual efforts began in

1989 with aerial occupancy surveys flown in late May or early June primarily for osprey and bald

eagles. Annual aerial productivity surveys flown in late July were initiated in 1991. In 1992 refuge

staff began visiting all known historical raptor nest locations in GMU 12 to document their status and

organize them into territories based on occupancy records. Additionally, helicopter surveys for cliff

7nesting raptors in the Cheslina River drainage of the Refuge were conducted in July 1995-1996

(Table 3). Since 2001, Tetlin Refuge has assumed responsibility for all raptor occupancy and

productivity surveys in GMU 12, including the Tanana River peregrine falcon surveys upstream of the

Robertson River.

The breeding biology and behavior, nesting habitat and diet of northern hawk owls in GMU 12 were

examined in a cooperative study during 2000-2001 (Shook 2002). A standardized early spring owl

survey was initiated near Northway in 2000 in cooperation with Boreal Partners In Flight.

As of 2005, 485 nests in 256 nesting territories for 11 raptor species have been identified in GMU 12

by the collective efforts discussed above. Since 1961, bald eagles, osprey and peregrine falcon nests

have accounted for 81% of the raptor nests documented in GMU 12. Between 41 to 67 bald eagle

nesting territories, 31 to 42 osprey nesting territories and 3 to 16 peregrine falcon nesting territories

have been surveyed annually since 1991 (Tables 4, 5 and 6). Limited numbers of nesting territories of

other species are also monitored, and include: golden eagle, northern goshawk (Accipiter gentilis), red-

tailed and Harlan’s hawks (Buteo jamaicensis), American kestrel (Falco sparverius), great horned owl

(Bubo virginianus), great gray owl (Strix nebulosa), northern hawk-owl, and common raven (Corvus

corax).

OBJECTIVES

The objectives of the “Tetlin NWR Wildlife Inventory Procedures for Raptors” (USFWS 1998) are to

(1) identify raptor nesting territories and breeding habitat within GMU 12; (2) monitor changes in nest

occupancy, reproductive success, and productivity of osprey, bald eagle, and peregrine falcon

populations in GMU 12; and (3) continue to identify new nests and territories of all raptor species for

future monitoring. Secondary objectives include acquiring information on raptor habitat and

environmental health and quality, especially relating to aquatic ecosystems, and documenting raptor

food habits and behavior. This report summarizes all monitoring efforts and other refuge activities

relating to raptors in 2004 and 2005.

8STUDY AREA

The Upper Tanana Valley is located in east central Alaska at the headwaters of the Tanana River

(Figure 1). GMU 12 encompasses the entire drainage of the Tanana River basin upstream of the

Robertson River confluence and the White River drainage within Alaska. The study area includes

approximately 14,000 km2 of GMU 12 bordered to the northeast by the divide along the Tanana-

Yukon Highlands south of the Forty Mile and Ladue River drainages, to the west and south by the

crest of the Mentasta and Nutzotin Mountains of the Alaska Range (Orth 1971), and to the east by

Yukon, Canada. The portions of GMU 12 south of the crest of the Alaska Range are not surveyed by

Tetlin Refuge staff.

The vegetation is typical of much of interior Alaska. Upland vegetation is boreal forest consisting

primarily of black spruce (Picea mariana) in wet and poorly drained areas and white spruce (P.

glauca) on drier sites (USFWS 2000). Quaking aspen (Populus tremuloides) commonly occurs on

well drained south facing slopes, and along with paper birch (Betula papyrifera) often occur in recently

burned or disturbed areas. Balsam poplar (P. balsamifera) is common along water courses. As

elevation increases, dense spruce gives way to open spruce woodlands mixed with tall shrubs, then

dwarf-shrub communities, and finally alpine tundra. Shrubs are most common along streams and

water bodies, within recently burned areas, and along gullies that drain alpine tundra. The shrub

component is primarily willow (Salix spp.), alder (Alnus spp.), and dwarf birch (B. spp.). Within the

study area are extensive wetlands and thousands of water bodies ranging from <1 ha to several square

kilometers in size, which osprey, bald eagles and peregrine falcons depend upon for most of their

nesting sites and foraging areas. Elevation ranges from 450 m in the lower end of the valley to 900 m

in the upper end, with mountain peaks ranging from approximately 1800 m to over 2800 m in the

Alaska Range along the southern boundary of the study area. All of the currently documented raptor

nesting territories surveyed in GMU 12 are below 1500 m elevation.

METHODS

Aerial or ground-based nest occupancy surveys are conducted annually during the incubation period of

target species, and productivity surveys are conducted after eggs hatch but before young fledge

(Steenhof 1987). Over the past decade, we found that the optimum time period for a single aerial

9occupancy survey for both bald eagles and osprey is 18 to 31 May in the Upper Tanana Valley.

Surveys started earlier may miss osprey that haven’t begun incubation and later surveys may miss bald

eagle pairs with failed nests that have abandoned their territories. Aerial productivity surveys are

conducted optimally from 20 to 28 July for both osprey and bald eagles. Aerial raptor surveys must be

flown by a slow flying fixed-wing aircraft (<130 km/hr [80 mph]) with good visibility (Piper Supercub

PA18, Aviat Husky, etc), or by helicopter.

Peregrine falcons are best surveyed from 18 May to 7 June to establish occupancy and the location of

the current nest site, and then revisited from 4 to 20 July to assess success and productivity. Cliffs are

observed from the ground at a distance (usually 100-400m or more) with high quality binoculars and

scopes with tripods. River boats (jet or propeller) are the usual means of transport, but canoes are used

occasionally and cars are used to access highway nest sites. In rare circumstances, we will use a

helicopter when available for productivity nest checks when ground observations are not likely to be

completed on the more remote territories. Survey crews are led by a raptor biologist with experience

in the techniques used to determine occupancy and productivity of peregrine nesting territories.

Depending on the amount of available nesting habitat and its history of use, each bluff and cliff along

the survey routes is observed for up to 2 hours each (4 hours for cliffs with historical use) or until

observations support occupancy, breeding and /or productivity status. When occupancy is difficult to

determine, cliffs may be revisited at a later time if possible. Peregrine nestling ages are estimated

during productivity surveys using techniques in Cade et al. (1996) and hatch dates are estimated by

backdating. We attempt to observe the legs of all perched peregrine adults to determine if USFWS

aluminum and color leg bands are worn and record the numbers when readable.

Data collected during each survey have been recorded on Raptor Observation Record Cards (raptor

cards) for all surveyed nests and nest cliffs in GMU 12 since 1989 (USFWS 1989, Figure 2).

Recorded data includes the number of adults, their behaviors, breeding evidence, the number of young

(and age estimate for peregrine nestlings), and nest location, situation (tree or cliff description) and

status at each nest site. Nest locations are recorded on 1:63,360 scale USGS maps and assigned an

identifier following the format on raptor cards in chronological order of discovery. A Global

Positioning System (GPS) receiver is used to determine the latitude and longitude for each nest and for

10display in a Geographical Information System (GIS).

A nesting territory is defined as an area that contains, or historically contained, one or more nests (or

scrapes) within the breeding range of a pair of mated birds and where no more than one pair of the

same species has ever nested at one time (Steenhof 1987). A supernumerary nest is an unoccupied

alternate nest within the nesting territory of one pair of birds that is used some years to raise young and

is maintained and visited by the adult pair. Four parameters are examined annually in analyzing raptor

population trends: (1) territories surveyed; (2) occupancy; (3) success; and (4) productivity.

Territories surveyed is the total number of nesting territories surveyed in a given year, not including

territories where all known nests are destroyed or have disappeared. Occupancy is the percentage of

nesting territories surveyed that were occupied during incubation. A nesting territory is occupied if

evidence is found of breeding (an incubating adult, eggs or young in a nest), or two adults are present

in the territory (Postupalsky 1974). Occupancy is unknown when no bird shows an affinity for the

territory during the breeding season and observers spent less than four hours at the territory during the

incubation period (USFWS 1989). Success is the percentage of occupied nesting territories with

breeding documented and known outcomes in which at least one young is known to survive to fledging

age (80% of average age at first flight). Productivity is the mean number of young fledged in

successful nests per occupied nesting territory with breeding documented and known outcome. Mean

brood size is the mean number of young fledged per successful nesting territory and may be useful for

comparisons with other studies without occupancy data. All territory location and nest data, and each

nest observation from all raptor cards since 1989 (n = 4033 observations), are entered in a Microsoft

Access database. This comprehensive relational database follows the raptor card format and a template

is available from the authors. Detailed procedures are discussed in the Refuge Wildlife Inventory and

Monitoring Plan (USFWS 1998).

We made 269 observations of 158 nest sites in 121 raptor nesting territories in GMU 12 in 2004. We

flew 18 survey hours and traveled 420 miles by boat on the Tanana, Chisana and Nabesna rivers.

Aerial occupancy surveys were conducted on 24, 25 and 27 May using a Piper Supercub PA-18.

Occupancy surveys were conducted by boat and foot along the Tanana River from the Northway Road

(on the Chisana River 4 miles above the confluence) to the Robertson River on 1-3 June, the Nabesna

11River from the confluence up to the Cheslina River on 20 May, and the Chisana River from the

confluence to Scottie Creek on 9-11 June. The Alaska Highway corridor from Tok to Scottie Creek

was surveyed by foot and vehicle on 1 and 7 June. Aerial productivity surveys were conducted on 28-

29 July in a Piper Supercub PA-18 throughout GMU 12 and on 15 July by helicopter (Robertson R-44)

for 2 additional peregrine bluffs. Productivity surveys on the same section of the Tanana River were

conducted on 12-13 July by boat and along the Alaska Highway corridor by foot and vehicle on 14 and

29 July.

In 2005, we made 280 observations at 154 nest sites in 114 raptor nesting territories. We flew 16

survey hours and traveled 465 miles by boat on the Tanana, Chisana and Nabesna rivers. Aerial

occupancy surveys were conducted on 23 and 24 May using a Piper Supercub PA-18. Occupancy

surveys were conducted by boat and foot along the Tanana River from the Northway Road (on the

Chisana River 4 miles above the confluence) to the Robertson River on 31 May to 2 June, the Nabesna

River from the confluence up to 5 miles above the Cheslina River on 18 May, and the Chisana River

from the confluence to 5 miles above Scottie Creek on 17 May. The Alaska Highway corridor from

Tok to Scottie Creek was surveyed by foot and vehicle on 16 and 31 May. Aerial productivity surveys

were conducted on 20, 21 and 26 July in a Piper Supercub PA-18 throughout GMU 12, and on 12 and

13 July by helicopter (Robertson R-44) for 2 additional peregrine bluffs. Productivity surveys on the

same section of the Tanana River were conducted on 12-13 July by boat and along the Alaska

Highway corridor by foot and vehicle on 16 and 18 July. Many nest observations were also recorded

during other refuge or personal activities and included in our database. Data presented in this report

supersedes data presented in previous progress reports.

RESULTS AND DISCUSSION

Bald Eagle

In 2004, bald eagle nest occupancy (56.5%) was well below the long-term (1991-2003) average of

68.0% ± 3.64 (mean ± 95% C.I.) for the 62 territories surveyed (Table 4; Figure 3). Bald eagle nesting

success (21.9%) and productivity (0.22 young/occupied nest) were both the lowest recorded, and well

outside the expected range (1991-2003; x = 55.16% ± 5.94; x = 0.70 ± 0.08). We hypothesize that 2

factors may have contributed to extremely low bald eagle success and productivity in 2004. First, we

12may have missed an unknown number of fledglings that left their nests before the aerial productivity

surveys on 28-29 July. Although these dates were near the latest recommended (31 July) for bald

eagles by the Refuge Inventory and Monitoring Plan (USFWS 1998), we suspect some pairs may have

initiated nesting earlier than usual this year, perhaps influenced by mild late winter and spring weather

conditions. We moved up our productivity survey in 2005 a few days (20, 21 and 26 July) to elude this

possible problem (see below). Second, dense smoke and extremely high temperatures during the

nesting period may have caused heat stress or difficulties in foraging for prey, resulting in low success

and productivity. Unusual environmental factors this year included about 3 months of smoky

atmospheric conditions from mid-June to mid-September caused by over 1.6 million acres of forest

fires burning inside of GMU 12 and within 80 miles of its northern boundary. June 2004 had both the

highest mean monthly temperature (62.03°F) and the highest mean monthly maximum temperature

(75.1°F) on record for Northway for all months for the station’s period of record (September 1949 to

December 2005; Northway FAA Airport, unpublished weather records, Western Regional Climate

Center, Reno, NV). Additionally, both mean monthly temperatures (57.26°F) and mean monthly

maximum temperatures (69.44°F) for a composite of May/ June/ July 2004 were also the highest

recorded for the same 3 month period during the same period of record.

Bald eagle observations in 2005 were more consistent with the average, lending support to the

suspicion that some fledglings were probably missed in 2004. Bald eagle nest success (51.5%) in 2005

improved to expected ranges (1991-2004; x = 52.78% ± 7.21), however occupancy (57.6%) and

productivity (0.55) were lower than average (1991-2004; x = 67.17% ± 3.73; x = 0.66 ± 0.10

respectively). There appeared to be a declining trend in both bald eagle success and productivity since

2002 (Table 4; Figure 3). For the combined years 2002, 2003, and 2005, mean success ( x = 50.0%)

was within expected values, however productivity ( x = 0.54) was well below the prior long-term mean

(1991-2001; x = 56.2% ± 6.83; x = 0.73 ± 0.08 respectively).

Bald eagle nesting success in GMU 12 was comparable to other parts of Alaska while productivity was

generally lower than those areas with more abundant fish resources. Productivity for the seven states

covered under the Pacific Bald Eagle Recovery Plan averaged 0.93 young/occupied nest from 1978 to

131985, slightly below the USFWS target for an average of 1.0 to remove the species from the

threatened species list (USFWS 1986). Merkens et al. (1999) found a minimum productivity of 0.86

young/occupied nest (1995) and 0.71 (1997) for bald eagles nesting in the Williston Reservoir area of

north-central British Columbia in the 2 years studied. In comparing six bald eagle populations in

Alaska, Maine, Florida and the Great Lakes area, Sprunt et al. (1973) found that nesting territory

success greater than 50% and minimum productivity of 0.70 young/occupied nest was required to

maintain stable bald eagle populations. Mean nesting territory success (52.7%) and productivity (0.65)

of bald eagles in GMU 12 from 1991-2005 approximated levels suggested by Sprunt et al (1973). The

specific factors affecting bald eagle territory occupancy, success and productivity in GMU 12 are

unknown.

Osprey

In contrast to bald eagles, osprey had an excellent breeding season in 2004. Although osprey nest

occupancy (73.5%) was within the expected range (1991-2003; x = 75.96% ± 4.08), success (70.0%)

and productivity (1.45) were both among the top 3 years and well above the respective 13-yr averages

( x = 55.85% ± 6.49; x = 1.02 ± 0.17; Table 5; Figure 4). The hot smoky summer weather did not

appear to adversely affect osprey success and productivity. In 2005, osprey nest occupancy (77.4%),

success (62.5%) and productivity (1.13) were all within expected ranges (1994-2004; x = 75.79% ±

3.79; x = 56.86% ± 6.32; x = 1.05 ± 0.17 respectively).

The number of osprey territories surveyed has decreased from the recent high of 38 in 2000 and 2001

to 31-34 from 2002 to 2005. This attrition was primarily due to the destruction of nests by storms and

we have been unable to locate many replacement nests. A shortage of suitable nest trees within osprey

territories may be a limiting factor. Productivity appeared to be increasing since the record low

observed in 1997 (R² = 0.319; Figure 4). The 1991-2005 mean productivity in GMU 12 ( x = 1.06 ±

0.16; Table 5) was comparable to that determined by Merkens et al. (1999), who found a minimum

productivity of 1.18 (1995) and 1.12 (1997) for osprey nesting in the Williston Reservoir area of north-

central British Columbia; these 2 years coincide with the record high of 1.50 (1995) and low of 0.45

(1997) in GMU 12.

14

Weather has been proposed as a factor in determining raptor territory success and productivity

(Wetmore and Gillespie 1976, Grubb 1977, Stinson 1978). Hughes (1987) found no relationship with

osprey territory success or productivity and snow cover, freeze-up or break-up dates, and winter or

spring temperatures in the Tetlin-Northway Flats from 1984-87. Machmer and Ydenberg (1990) found

that extended periods of high wind velocity reduced hunting success of osprey in British Columbia

because of deteriorating water surface conditions. Reduced hunting success could translate into

reduced territory success and productivity. Hughes hypothesized that the Tok River fire of 1990

impacted territory success and productivity in the Tetlin Lake area during 1991 and 1992 by increasing

nutrients and thus algae density into the wetlands (J. Hughes, Alaska Department of Fish and Game,

Personal Communication). This may have reduced visibility through the water enough to cause a

decrease in the ability of osprey to locate fish. Age and experience of adults should also be considered

as factors in determining territory success and productivity (Poole 1985).

American Peregrine Falcon

Nest occupancy was 100% for the 16 peregrine falcon territories surveyed in 2004, higher than the

1991-2003 average ( x = 88.07% ± 7.43; Table 6; Figure 5). However, falcon nest success (78.6%) and

productivity (1.93 young/occupied nest) were both below expected ranges ( x = 88.33% ± 8.36; x =

2.35 ± 0.42, respectively). Hatch dates for peregrine chicks in GMU 12 in 2004 ranged from 6 June to

27 June with a mean hatch date of 16 June (n=27; 66.7% within x ± 3 days). Despite low success and

productivity in GMU 12, our values were much higher than two other surveys conducted in eastern

interior Alaska during 2004 (N. Guldager, National Park Service, Personal Communication, 2006,

Shook and Ritchie 2004; Table 7). On the upper Yukon River, smoke from the many wildfires in the

area prevented completion of productivity surveys by staff of Yukon-Charley National Preserve for all

the occupied nest sites (n=52). Of the 39 territories (75%) that were monitored, 41% were successful

and productivity was 0.82 young per occupied nest. Also in 2004, ABR Inc. staff completed a

peregrine falcon survey on the forks of the Fortymile River despite heavy smoke conditions. Thirty-

four peregrine falcon nest sites were surveyed and 26 (76.5%) were occupied. Nest success (50%) and

productivity (1.0) were slightly higher on the Fortymile River than on the upper Yukon River.

15In 2005, falcon nest occupancy (87.5%), success (81.8%) and productivity (2.00) in GMU 12 were

within expected ranges (1991-2004; x = 88.92% ± 7.08; x = 87.63% ± 7.86; x = 2.32 ± 0.40,

respectively; Table 6; Figure 5). Hatch dates for GMU 12 peregrine chicks in 2005 ranged from 11

June to 23 June with a mean hatch date of 16 June (n=19; 73.7% within x ± 4 days). The number of

peregrine falcon nesting territories documented in the Upper Tanana Valley has more than doubled

since 1999; from 8 to 20 (16 were surveyed in both 2004 and 2005). Productivity (2.00) and mean

brood size (2.44 young/successful nest) was higher in 2005 than in 3 Alaska study areas north of GMU

12 (N. Guldager, National Park Service, Personal Communication, 2006, McIntyre and Burch 2005,

D. Payer, U.S. Fish and Wildlife Service, Personal Communication, 2005; Table 7). On the upper

Yukon River, 50 peregrine pairs had 64.6% success, productivity was 1.46 young per occupied nest

and mean brood size was 2.26. The Charley River, also in Yukon-Charley National Preserve, was

surveyed for peregrines in 2005 for the first time since 2000; although nest success (83.3%) was

slightly higher than GMU 12, productivity (1.58) and mean brood size (1.9) was lower. A single mid-

July peregrine survey was conducted on 166 km of the Porcupine River in Arctic National Wildlife

Refuge; productivity could not be estimated, but mean brood size (2.32 young/successful nest) was

slightly lower than GMU 12 in 2005.

The long-term averages for peregrine falcon nesting success (1991-2005; x = 87.24% ± 7.35),

productivity ( x = 2.30 ± 0.37) and mean brood size ( x = 2.60 ± 0.29) in GMU 12 were higher than all

other eastern interior Alaska study areas with available data (Jacobs 2003, Ritchie and Shook 2003,

Shook et al. 2003, Ambrose 2004, Shook and Ritchie 2004; Tables 6 and 7). Peregrine falcons along

the Tanana River from the Alaska Highway bridge to Nenana had 74.2% mean success, 1.99 mean

productivity and 2.68 mean brood size for 1991-2003. The population in our study area overlaps the

Tanana River population studied by Shook et al. (2003) with a maximum of 7 territories in common

surveyed (in 2003). Slightly lower were the means for success (69.0%), productivity (1.67) and mean

brood size (2.40) on the Upper Yukon River for 1975-2004 (Ambrose 2004). Ritchie and Shook

(2003) surveyed peregrine falcons in selected drainages of the Yukon-Tanana uplands in 1995-2003;

mean success, productivity and mean brood size was 66%, 1.6 and 2.4 respectively. Complete surveys

for peregrine falcons nesting in the Fortymile River drainage north of our study area (Figure 1) were

conducted in 2000-2001 (Jacobs 2003) and in 2004 (Shook and Ritchie 2004); mean success,

16vely.

everal factors can influence success and productivity of peregrine falcons, including weather, habitat,

ted to

y

d

occupied

=

(n=7) with

productivity and mean brood size for those 3 years combined was 61%, 1.02 and 1.68 respecti

S

prey availability and abundance, age and experience of adults, density of occupied territories,

environmental contaminants and disturbance (Ambrose 2003). Two factors may have contribu

higher success and productivity of peregrine falcons in GMU 12. We suspect the peregrine falcon

population in our study area may have better access to higher quality habitat and thereby higher pre

availability. Many falcon nests are in close proximity to extensive wetlands that support plentiful

populations of waterfowl, shorebirds, other waterbirds and passerines. This diverse prey base coul

translate to increased success and productivity for local nesting falcons. Jacobs (2003) found that

falcon nests that were within 6 km (3.7 miles) of a pond had higher productivity than those farther

from ponds in the Fortymile River drainage. Jacobs (2003) also found a significant positive

relationship between falcon productivity and the presence of ponds within 3km (1.9 miles) of

nests using data from the Tanana River population. Further evidence comes from a comparison of

occupied nests within our study area that were subject to similar weather conditions in 2003-2005.

Nests adjacent to the abundant wetlands of the Tetlin-Northway Flats (n=7; Figure 1) were 100%

successful, and produced a mean of 2.88 (95% C.I. = 0.53) young/occupied nest (mean brood size

2.88 ± 0.53) for the 3 years combined. The remaining territories with breeding pairs in the

northwestern portion of GMU 12 along the Tanana River below the Alaska Highway bridge

more restricted wetland access had lower success ( x = 73.7% ± 11.3), productivity ( x = 1.79 ± 0.57)

and mean brood size ( x = 2.43 ± 0.45) for the same 3 years. The relationships between wetlands and

peregrine productivity in GMU 12 are unclear and deserve further study.

Four falcon pairs that established new nests on road cut banks and in rock quarries in GMU 12

est in

nted

airs

adjacent to the Alaska Highway from 1995 to 2000, were among the first documented pairs to n

“artificial” habitats in Alaska (Ritchie et al. 1998). Another pair occupied a new territory on an

eroding permafrost silt bluff along the Tanana River in 2001-2002, but breeding was not docume

in either 2001 or 2002, and the bluff was abandoned in 2003 and 2004; this falcon territory was not

included in the occupancy and productivity summary beginning 2004. A new pair documented in

2003, occupied a territory about 1 km from the Tanana River lying halfway between two existing p

17t

ow

mi)

Tanana

wls

dardized early spring owl survey was initiated in 2000 in cooperation with Boreal Partners in

4

d

that were 10 km apart, effectively decreasing that spacing to 3.7 and 6.0 km between occupied nes

sites. In 2004 a new pair occupied a vacant golden eagle nest cliff in the upper Cheslina River on the

refuge, establishing the highest known elevation for a peregrine pair in GMU 12 at approximately 1070

m (3500 ft). Two more new nesting territories were discovered in 2004 on the refuge and are the

easternmost known falcon nests in GMU 12. One pair nested on a man-made quarry ledge at the end

of a half mile access road off the Alaska Highway, increasing the total to 5 falcons nesting on man-

made “artificial” cliffs in GMU 12. The second pair was found on a small forested rock outcrop bel

Scottie Creek on the Chisana River on a site that we’ve been watching for a decade expecting falcons

to use some day. New breeding pairs appear to be “filling in the gaps” on sometimes marginal or man-

made sites, and often some distance from the rivers where most of the existing bluffs are already

occupied. Distances between current neighboring nest sites (n = 16 nests) ranged from 3.7 km (2.3

to 39.6 km (24.6 mi) along the 177 km (110 mi) long Tanana and Chisana rivers and Alaska Highway

corridors in GMU 12, with 6 of those distances equal to 7.1 km (4.4 mi) or less. This population may

be reaching a saturation point in the Upper Tanana Valley, as the availability of bluffs and “suitable”

nesting habitat begin to limit the number of breeding falcon pairs. The falcon population has

continued to expand since 1975-1976, when no territories were successful either year along the

River from the Alaska Highway bridge to Nenana, when at least 16 territories and 45 major cliffs were

surveyed (Haugh 1976).

O

A stan

Flight. Fifteen points at 1.6 km (1 mi) intervals were established on the Alaska Highway along a

portion of the Northway Breeding Bird Survey route. The survey was completed on 22 March 200

and we detected 4 great horned owls. In 2005, the survey was conducted on 24 March and we detecte

6 great horned owls and 1 boreal owl (Aegolius funereus). Previous refuge owl surveys conducted on

the same route in 2000, 2001 and 2003 detected a total of 11 great horned owls, 8 boreal owls and 1

great grey owl. Over the next few years we plan to vary the timing of the survey to determine an

optimal survey period and develop a long-term owl monitoring protocol.

18ther Raptors

ess and productivity were not determined for other raptor species due to insufficient

re

nts,

fall migration banding station located seven miles west of Tok has been operated by refuge staff

r

and 1

1

O

Occupancy, succ

data. No helicopter surveys for cliff nesting raptors have been conducted since 1996. Other raptor

species occurring in GMU 12 (Table 1) were only monitored incidentally. Many of these raptors we

documented during other monitoring activities such as Christmas Bird Count, North American

Migration Count, waterfowl pair and brood surveys, Breeding Bird Surveys, Off-road Point Cou

hare pellet transects, small mammal transects, invasive plant surveys and other refuge activities.

Although not raptors, common raven nests were often encountered during raptor surveys and

monitored.

A

daily during August and September since 1993. Twenty mist nets were open for the 6 hours after

sunrise daily (weather permitting) for the capture and banding of passerines. Although designed fo

passerines, some small raptors such as sharp-shinned hawks (Accipiter striatus) were captured and

banded at this station. While the fall migration banding station was open from 28 July to 29

September 2004, 10 sharp-shinned hawks (3 after-hatch year females and 7 hatch year males)

boreal owl (hatch year) were captured and banded. In 2005, the station was open from 30 July to 27

September and 8 sharp-shinned hawks were captured and banded (1 after-hatch year female, 1 hatch

year female, 1 after-hatch year male and 5 hatch year males). Seventy-four sharp-shinned hawks and

boreal owl (and 5 raptor-like northern shrikes; Lanius excubitor) were captured and banded at this

station during fall migration since 1993. An additional 5 sharp-shinned hawks were captured at the

station during spring migration banding during the 5 years (1994-1998) of operation in spring (late

April through early June). Other raptor species captured at this station since 1993 but not banded

include 2 boreal owls and 1 northern hawk-owl.

19ACKNOWLEDGMENTS

We gratefully acknowledge the reports and data obtained by Robert J. Ritchie and John E. Shook of

Alaska Biological Research, and the assistance provided by Tetlin National Wildlife Refuge staff

Merben R. Cebrian, Michael Collins, Susy Grimes and Carrie Hisaoka. Tetlin Refuge pilot Jim Ellis

flew many safe hours to contribute to this database. We especially appreciate refuge biologist Gail H.

Collins for her editing and tireless efforts in helping us create and improve our raptor Access database.

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24

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Table 1. Status and abundance of raptors known to occur in GMU 12, Alaska1.

Species Abundance Breeding and Migrant StatusFALCONIFORMES: Catartidae: Turkey Vulture (Cathartes aura) accidental nonbreeder, visitant Accipitridae: Osprey (Pandion haliaetus) uncommon breeder, long distance migrant Bald Eagle (Haliaeetus leucocephalus) common breeder, short distance migrant Northern Harrier (Circus cyaneus) uncommon breeder, medium distance migrant Sharp-shinned Hawk (Accipiter striatus) uncommon breeder, medium distance migrant Northern Goshawk (Accipiter gentilus) rare breeder, resident Swainson's Hawk (Buteo swainsoni) casual nonbreeder, visitant Red-tailed Hawk (Buteo jamaicensis) uncommon breeder, medium distance migrant Rough-legged Hawk (Buteo lagopus) uncommon nonbreeder, short distance migrant Golden Eagle (Aquila chrysaetos) uncommon breeder, medium distance migrant Falconidae: American Kestrel (Falco sparverius) uncommon breeder, medium distance migrant Merlin (Falco columbarius) rare breeder, long distance migrant Gyrfalcon (Falco rusticolus) rare breeder, short distance migrant Peregrine Falcon (Falco peregrinus) rare breeder, long distance migrant STRIGIFORMES: Strigidae: Great Horned Owl (Bubo viginianus) uncommon breeder, resident Snowy Owl (Nyctea scandiaca) causal nonbreeder, visitant Northern Hawk Owl (Surnia ulula) uncommon breeder, resident Great Gray Owl (Strix nebulosa) rare breeder, resident Short-eared Owl (Asio flammeus) rare breeder, medium distance migrant Boreal Owl (Aegolius funerius) rare breeder, resident

1Abundance and Status from from Kessel and Gibson (1978) where: common - species occurs in all or nearly all proper habitats, but some areas of presumed suitable habitat are occupied sparsely or not at all and/or the region regularly hosts large number of the species; uncommon - species occurs regularly, but utilizes very little of the suitable habitat, and/or the region regularly hosts relatively small numbers of the species, not observed regularly even in proper habitats; rare - species occurs, or probably occurs, regularly within the region, but in very small numbers; casual - a species beyond its normal range, but not so far but what irregular observations are likely over a period of years; usually occurs in very small numbers; accidental - a species so far from its normal range that further observations are unlikely; usually occurs singly; resident - a species present throughout the year; migrant - a seasonal transient between wintering and breeding ranges; breeder - a species known to breed; visitant - a nonbreeding species. Migrant status from USFWS (2000) where: long distance migrant- winters predominanatly south of the U.S.-Mexico border; medium distance migrant- majority winters north of U.S.-Mexico border, but part of the population winters south of it; short distance migrant- North American migrant that does not usually winter south of the U.S.-Mexico border.

25

26 Table 2. Bald eagle and osprey surveys conducted by agencies and contractors in GMU 12, Alaska, 1983-2005.

Year 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05

USFWS End. Spp. Tanana River BAEA- aerial Occupancy

Tanana River

ADF&G Tetlin Lk/ N TNWR

OSPR- PROD only Tetlin Lk

ADF&G Tetlin Lk/ N TNWR

OSPR/BAEA aerial/ ground

OCC/PROD Tetlin Lake and N TNWR only ***

ABR, Inc. Tok area / all raptors ground

All raptors grnd search

Tok area

Tetlin NWR GMU 12 aerial platform

BAEA/OSPR

aerial nest platform search

*

Tetlin NWR BAEA/OSPR-TNWR

**

Tetlin NWR GMU 12 aerial OCC only

BAEA /OSPR OCC

Tetlin NWR GMU 12 aerial OCC/PROD

BAEA/OSPR aerial OCC/PROD in all of GMU 12 ***

Bald Eagle= BAEA, Osprey= OSPR, both spp = BAEA/OSPR , 2 annual surveys for both species occupancy and productivity= OCC/PROD. * Same aerial platform search. ** Boat/ ground search for BAEA/OSPR nests on TNWR (1 visit). *** Surveys in 1991-1993 were conducted jointly by ADF&G and Tetlin NWR.

27 Table 3. Peregrine falcon surveys conducted by agencies and contractors in GMU 12, Alaska, 1979-2005.

Year 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05

USFWS End. Spp. Tanana River *

Tanana River *

ADF&G Tanana River

Tanana River

ABR, Inc. Tanana River

Tanana River

Tetlin NWR Tanana River

Tanana River

Tetlin NWR Alaska Highway

Alaska Highway

Tetlin NWR Cheslina River Helicopter

h **

Cheslina River

All used 2 annual ground surveys for occupancy and productivity, except Cheslina River. * Tanana River survey is from Alaska Hwy bridge to Robertson River, except prior to 1985 survey began at Tanacross. ** Cheslina River drainage- peregrine falcon and golden eagle cliff nest search by helicopter in July for productivity only.

28

Table 4. Summary of nesting parameters in bald eagle territory status in Game Management Unit 12, Alaska, 1991-2005.

Occupied Occupied Mean Species

Year Territories Occupancy Breeding All Breeding with Occupied

Occupied # Young Occupancy

Success

Productivity

Brood Surveyed

Unknown

Unknown

Occupied

Known Outcome

Failed Successful

Fledged

% % * Size **

Bald Eagle

1991 41 19 1 22 10 5 5 7 53.7 50.0 0.70 1.40 1992

48 21 1 27 19 5 14 15 56.3 73.7 0.79 1.071993 50 15 3 35 32 12 20 24 70.0 62.5 0.75 1.201994 42 14 3 28 19 11 8 11 66.7 42.1 0.58 1.381995 47 15 0 32 31 15 16 20 68.1 51.6 0.65 1.251996 48 13 3 35 32 10 22 30 72.9 68.8 0.94 1.361997 44 10 2 34 32 18 14 20 77.3 43.8 0.63 1.431998 50 13 3 37 34 14 20 27 74.0 58.8 0.79 1.351999 57 18 1 39 38 18 20 27 68.4 52.6 0.71 1.352000 59 21 1 38 37 21 16 18 64.4 43.2 0.49 1.132001 64 18 2 46 42 12 30 40 71.9 71.4 0.95 1.332002 64 20 1 44 41 22 19 21 68.8 46.3 0.51 1.112003 67 19 0 48 46 22 24 26 71.6 52.2 0.57 1.082004 62 27 2 35 32 25 7 7 56.5 21.9 0.22 1.002005 59 25 1 34 33 16 17 18 57.6 51.5 0.55 1.06

Mean 1991-2003 52.38 16.62 1.62 35.77 31.77 14.23 17.54 22.00 68.00 55.16 0.70 1.26

SD 6.69 10.93 0.15 0.1395% C. I. 3.64 5.94 0.08 0.07

Mean 1991-2004 53.07 17.36 1.64 35.71 31.79 15.00 16.79 20.93 67.17 52.78 0.66 1.25 SD 7.13 13.77 0.19 0.14

95% C. I. 3.73 7.21 0.10 0.07 Mean 1991-2005 53.47 17.87 1.60 35.60 31.87 15.07 16.80 20.73 66.54 52.70 0.65 1.23

SD 7.30 13.27 0.19 0.1595% C. I. 3.69 6.72 0.10 0.08

* Productivity is the mean number of young fledged per occupied breeding territories with known outcome. ** Mean Brood Size is the mean number of young fledged per occupied successful territories.

29 Table 5. Summary of nesting parameters in osprey territory status in Game Management Unit 12, Alaska, 1991-2005.

Occupied Occupied Mean Species

Year Territories Occupancy Breeding All Breeding with Occupied

Occupied # Young Occupancy

Success

Productivity

Brood Surveyed

Unknown Unknown

Occupied

Known Outcome

Failed Successful

Fledged

% % * Size **

Osprey

1991 36 6 0 30 25 14 11 14 83.3 44.0 0.56 1.271992 42 8 0 34 27 16 11 19 81.0 40.7 0.70 1.731993 38 6 0 32 32 14 18 37 84.2 56.3 1.16 2.061994 38 10 0 28 8 3 5 7 73.7 62.5 0.88 1.401995 38 13 1 25 24 7 17 36 65.8 70.8 1.50 2.121996 37 6 4 31 26 11 15 27 83.8 57.7 1.04 1.801997 39 6 1 33 31 22 9 14 84.6 29.0 0.45 1.561998 38 11 0 27 27 8 19 26 71.1 70.4 0.96 1.371999 36 11 0 25 25 9 16 27 69.4 64.0 1.08 1.692000 38 8 0 30 30 13 17 35 78.9 56.7 1.17 2.062001 38 11 0 27 27 10 17 32 71.1 63.0 1.19 1.882002 32 12 0 20 19 9 10 22 62.5 52.6 1.16 2.202003 32 7 0 25 24 10 14 34 78.1 58.3 1.42 2.432004 34 9 2 25 20 6 14 29 73.5 70.0 1.45 2.072005 31 7 0 24 24 9 15 27 77.4 62.5 1.13 1.80

Mean 1991-2003 37.08 8.85 0.46 28.23 25.00 11.23 13.77 25.38 75.96 55.85 1.02 1.81

SD

7.51 11.92 0.31 0.3595% C. I. 4.08 6.48 0.17 0.19

Mean 1991-2004 36.86 8.86 0.57 28.00 24.64 10.86 13.79 25.64 75.79 56.86 1.05 1.83

SD

7.25 12.06 0.32 0.3595% C. I. 3.80 6.32 0.17 0.18

Mean 1991-2005 36.47 8.73 0.53 27.73 24.60 10.73 13.87 25.73 75.90 57.23 1.06 1.83

SD

7.00 11.71 0.31 0.3395% C. I. 3.54 5.93 0.16 0.17 * Productivity is the mean number of young fledged per occupied breeding territories with known outcome. ** Mean Brood Size is the mean number of young fledged per occupied successful territories.

30

Table 6. Summary of nesting parameters in peregrine falcon territory status in Game Management Unit 12, Alaska, 1991-2005.

Occupied Occupied # Mean Species

Year Territories Occupancy Breeding All Breeding with Occupied

Occupied Young Occupancy

Success

Productivity

Brood Surveyed

Unknown

Unknown

Occupied

Known Outcome

Failed Successful

Fledged

% % * Size **

Peregrine

1991 3 1 0 2 2 0 2 5 66.7 100.0 2.50 2.50Falcon 1992 4 0 1 4 3 0 3 6 100.0 100.0 2.00 2.00

1993 4 1 0 3 3 0 3 12 75.0 100.0 4.00 4.001994 6 1 1 5 4 0 4 13 83.3 100.0

3.25 3.25

1995 8 0 1 8 7 2 5 11 100.0 71.4 1.57 2.201996 8 3 1 5 4 2 2 4 62.5 50.0 1.00 2.001997 5 1 0 4 4 0 4 8 80.0 100.0

2.00 2.00

1998 5 0 0 5 5 1 4 13 100.0 80.0 2.60 3.251999 6 0 0 6 6 0 6 15 100.0 100.0

2.50 2.50

2000 9 0 1 9 8 2 6 12 100.0 75.0 1.50 2.002001 12 1 1 11 10 1 9 24 91.7 90.0 2.40 2.672002 12 0 1 12 11 1 10 27 100.0 90.9 2.45 2.702003 14 2 1 12 11 1 10 31 85.7 90.9 2.82 3.102004 16 0 2 16 14 3 11 27 100.0 78.6 1.93 2.452005 16 2 3 14 11 2 9 22 87.5 81.8 2.00 2.44

Mean 1991-2003 7.38 0.77 0.62 6.62 6.00 0.77 5.23 13.92 88.07 88.33 2.35 2.63

SD 13.67 15.37 0.78 0.6295% C. I. 7.43 8.36 0.42 0.34

Mean 1991-2004 8.00 0.71 0.71 7.29 6.57 0.93 5.64 14.86 88.92 87.63 2.32 2.62 SD 13.52 15.00 0.76 0.60

95% C. I. 7.08 7.86 0.40 0.31 Mean 1991-2005 8.53 0.80 0.87 7.73 6.87 1.00 5.87 15.33 88.83 87.24 2.30 2.60

SD 13.03 14.53 0.73 0.5895% C. I. 6.59 7.35 0.37 0.29 * Productivity is the mean number of young fledged per occupied breeding territories with known outcome. ** Mean Brood Size is the mean number of young fledged per occupied successful territories.

31

Table 7. Nesting success, productivity and mean brood size of peregrine falcon populations from selected surveys in eastern interior Alaska, 2004, 2005 and long term means.

* Productivity is the mean number of young fledged per occupied breeding territories.

Study Area

Year(s) Data

Collected

Success (%) Productivity * Mean Brood

Size ** Citation

Upper Tanana Valley (GMU 12), Alaska 2004 78.6 1.93 2.45 This report

Fortymile River, Alaska 2004 50.0 1.0 1.8 Shook and Ritchie 2004

Upper Yukon River, Alaska 2004 41.0 0.82 2.0 Ambrose and Florian

2004

Upper Tanana Valley (GMU 12), Alaska 2005 81.8 2.00 2.44 This report

Charley River, Alaska 2005 83.3 1.58 1.90 McIntyre and Burch 2005

Upper Yukon River, Alaska 2005 64.6 1.46 2.26 Guldager 2006 (Pers.

Comm.)

Porcupine River, Alaska 2005 86*** *** 2.32 Payer 2005 (Pers.

Comm.)

Upper Tanana Valley (GMU 12), Alaska

1991-2005 x

87.2 2.30 2.60 This report

Tanana River, Alaska 1991-2003 x

74.2 1.99 2.68 Shook et al. 2003

Yukon/ Tanana Uplands, Alaska

1995-2003 x

66 1.6 2.4 Ritchie and Shook 2003

Fortymile River, Alaska

2000, 2001, 2004

x 61 1.02 1.68 Jacobs 2003, Shook and

Ritchie 2004

Upper Yukon River, Alaska

1975-2004 x

69.0 1.67 2.40 Ambrose and Florian 2004

** Mean Brood Size is the mean number of young fledged per occupied successful territories. *** No occupancy survey conducted, % success estimated.

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Figure 1. Raptor survey area in the Upper Tanana Valley (GMU 12), Alaska.

33

Figure 2. U.S. Fish and Wildlife Service Raptor Observation Record Card.

34

Bald Eagle Occupancy, Success and Productivity 1991-2005 in GMU12, Alaska

0

20

40

60

80

100

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Year

Perc

ent O

ccup

ancy

and

Suc

cess

0.0

0.4

0.8

1.2

1.6

2.0

Prod

uctiv

ity

Occupancy % Success % Productivity

Figure 3. Bald eagle nesting occupancy, success and productivity in the Upper Tanana Valley (GMU 12), Alaska, 1991-2005.

35

Osprey Occupancy, Success and Productivity 1991-2005 in GMU12, Alaska

y = 0.039x + 0.746 R2 = 0.319

0

20

40

60

80

100

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Year

Perc

ent O

ccup

ancy

and

Suc

cess

0.0

0.4

0.8

1.2

1.6

2.0

Prod

uctiv

ity

Occupancy % Success % Productivity Linear (Productivity)

Figure 4. Osprey nesting occupancy, success and productivity in the Upper Tanana Valley (GMU 12), Alaska, 1991-2005.

36

Peregrine Falcon Occupancy, Success and Productivity 1991-2005 in GMU12, Alaska

0

20

40

60

80

100

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Year

Perc

ent O

ccup

ancy

and

Suc

cess

0.0

1.0

2.0

3.0

4.0

5.0

Prod

uctiv

ity

Occupancy % Success % Productivity

Figure 5. Peregrine falcon nesting occupancy, success and productivity in the Upper Tanana Valley (GMU 12), Alaska, 1991-2005.