Suncoast Shorebird Partnership (SSP)Charlotte Co. north to Pasco Co.

monitoring management advocacyeducation

research

• Federal, state, county, and municipal managers & biologists• Audubon of Florida• Academics• Volunteers

Area of data coverage:-Pinellas-Egmont Key-Sarasota-Manatee

The problems with data deficient species, specifically the least

tern, and an exploration of the watch list concept

Otherwise known as: why did the Least Tern only earn an initial Millsap score of 16? (beneath the American alligator)

Today I’ll cover:•Basic natural history of Least Tern•Our Least Tern data for 25% of Least Terns in Florida (150km of beach)•Why nearly all beach-nesting birds are data deficient•How the Millsap criteria has an inherent bias against beach-nesting birds•A potential solution for beach-nesting birds

Least Tern, smallest colonial seabird in North America

•Colonial nester

•Small clutch size

•Migratory

•Other subspecies are Federally listed due to habitat loss

Other open-beach nesters

American Oystercatcher: SSC

Black Skimmer: SSC

Wilson’s Plover: not listed

Ideal Least Tern HabitatOpen beach, little vegetation, no tall objects (e.g., trees, buildings for predator perches), level, low-silt sand. Ideally, not connected to a mainland (no terrestrial predators)

All open-beach nesting birds will get a low score for “Range” in the Millsap score. It is biased against species with linear and patchy distributions.

Rooftop Habitat

•Majority of nesting in our region

•Productivity (fledge/pair) has been higher on rooftops

•Gravel rooftops are being replaced with non-gravel roofs.

How does Millsap incorporate a major decline in rooftops? Rooftop nesting birds receive a lower score in section 7 “Ecological Specialization”

Rooftop productivity is high, but due to intensive help from volunteers.

Millsap does not take into account species whose numbers are higher because of human management. Without volunteers, productivity on rooftops would be very low.

Photo © Dave KandzPhoto © Dave Kandz

Photo © Ben Flower

Our Data Collection Search for colonies on all beaches & rooftops in region

Monitor beach colonies once/week

Monitor rooftop colonies once/3 weeks

Check for falling chicks 3-8 times/day

Conduct staging survey at the end of the season.

2002 2003 2004 2005 2006 2007 2008 20090

10

20

30

40

50 # of occupied rooftops

# of ground colonies

Number of colonies (Pinellas, Egmont Key, Manatee, and Sarasota)

2002 2003 2004 2005 2006 2007 2008 20090

500

1000

1500

2000

2500

3000

3500

Total adults - Rooftop

Total adults - Ground

Historic data from the 1960s in Sarasota indicates that there are only a fraction of the birds left.

Number of individuals during mid-May count

Location Productivity

Our data from staging survey 2002-2009 0.16

Gulf coast 1979-1981 0.59

New Jersey 1978-1982 0.48

Interior subspecies 1987-1990 0.47

California subspecies 2005-2008 0.36

Productivity in SW Florida is extremely low compared to productivity in the listed subspecies

and productivity 20 years ago.

I conducted a population viability analysis (PVA) for SW Florida using our productivity data (0.16) the “best case” estimates from publications for the California Least Tern (simulation was run 100 times)

If we had productivity levels as high as the California subspecies (0.36), the terns would be stable.

Summary of issues effecting beach-nesting birds using the Millsap criteria

1. Population size: not known for any of the open-beach nesters

2. Population trend: other than our data, no trend data exists

3. Range size: inherently biased against beach-nesting birds

4. Distribution trend: largely unknown

5. Population Concentration: OK

6. Reproductive potential: probably OK

7. Ecological specialization: biased against rooftop nesters

Problems getting data for Least Terns and other beach-nesting birds:•Christmas bird count data: can’t be used, species are migratory

•Breeding Bird Survey: can’t be used in Florida, little of coast is covered

•Birds of North America Account: most are published in 1990s, only uses published data. (the Red Knot BNA account does not indicate it is declining)

•FWC Shorebird database: entering data is voluntary and uneven, methods are not standard, numerous estimation errors of number of adults / nests, errors with double reporting colonies.

Potential problems using a viability panel for data deficient species:

“Least Terns are doing great in the Panhandle”

•Millsap requires good estimates of population size, range and distribution. Without this data, viability panels will have to estimate.

• Viability panels work best when you have many highly experienced experts and datasets. External experts are important. For the least tern, you have 2 scientists (myself and Marianne Korosy) with a combined 20 years of experience.

•Without data, strong personal biases may dramatically influence estimations.

Some suggestions:1. Open-beach nesting birds should be evaluated for meeting

IUCN criteria regardless of Millsap score. If there is not enough data, species should be judged “data deficient” (DD)

2. Species judged to be DD or for whom there appears to be reason to suspect a future decline should be placed on a special list “watch list”.

3. Monitoring plans should be developed with expert knowledge for DD species. I am happy to help and I have some specific ideas about Least Tern monitoring.

4. It may never be possible to get a good estimate of population size for some species. Productivity should be used as a surrogate or an ancillary measure. Declines in productivity are as important as population size.