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Title Page Evaluating American Oystercatcher Productivity: A Comparison of Nest Success Estimation Methods Photo: www.birdsbykim.com Tom Virzi, Ph.D. Candidate.

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Presentation on theme: "Title Page Evaluating American Oystercatcher Productivity: A Comparison of Nest Success Estimation Methods Photo: www.birdsbykim.com Tom Virzi, Ph.D. Candidate."— Presentation transcript:

1 Title Page Evaluating American Oystercatcher Productivity: A Comparison of Nest Success Estimation Methods Photo: Tom Virzi, Ph.D. Candidate Department of Ecology, Evolution and Natural Resources Rutgers, The State University of NJ

2 Research Objectives Determine Breeding Habitat Requirements and Causes of Nest Failure Compare Reproductive Success Between Beach and Marsh Nesting Pairs Assess the Effects of Human Disturbance on Nest Success Photo:

3 Barrier Beach - Optimal Habitat Salt Marsh - Sub-Optimal Habitat Nest Success Lower in Sub-Optimal Habitat Development/Disturbance on Beaches Pushes Oystercatchers into Sub-Optimal Habitat Hypotheses Photo:

4 Methods Survey beaches, marsh and inlet islands for pairs/nests from March 1 - July 31 GPS all pairs/nests found Monitor nests every 3-4 days Additional data recorded during nest checks: –Point count of gulls –Presence/absence of mammal tracks –Human activity within 100m of nests/territories Methods

5 Nest Success Estimation Methods Apparent Nest Success –Biases High Mayfield Method –Daily Survival Probabilities Program MARK –Information Theoretic Approach (AIC) –Covariates

6 Nest Success Terms Apparent Nest Success Measures –Hatch Success (# Nests Hatched / # Nests Found) –Nest Success (# Nests Fledged / # Nests Found) DSR – Daily Survival Rate –Nest DSR –Brood DSR Hatch Success (Nest DSR^28 Days) Brood Success (Brood DSR^42 Days) Nest Success (Hatch Success x Brood Success)

7 NJ AMOYs North Coast – 8 Pairs Central Coast – 25 Pairs South Coast – 35 Pairs Beach Breeding Pairs in New Jersey

8 Study Sites Sites selected over a gradient of human disturbance Public Use Beach Closures ORV Use Island Beach State Park HighMinimal Area All Year Forsythe NWR Holgate Division LowEntire Beach Winter Only Stone Harbor Point MedLarge Area Winter Only IB HG SH

9 Holgate Holgate Beach – 23 Pairs Marsh – 3 Pairs Island – 1 Pair Total Pairs – 27 (Beach 2005 – 18)

10 Stone Harbor Beach – 19 Pairs Marsh – 11 Pairs Island – 8 Pairs Total Pairs – 38 (Beach 2005 – 20)

11 Island Beach Beach – 5 Pairs Marsh – 11 Pairs Island – 25 Pairs Total Pairs – 41 (Beach 2005 – 5)

12 Results

13 Comparison of Nest Success Estimation Methods Method Pooled Apparent - Hatch Success15.0%26.8%25.9%32.8% - Nest Success5.0%15.5%18.8%17.9% Mayfield - Hatch Success0.6%20.0%12.9%18.4% - Brood Success0.3%35.8%57.1%50.0% - Nest Success0.0%7.2%7.4%9.2% Program MARK - Hatch Success7.4%20.0%14.0%16.7% - Brood Successn/a36.2%57.3%41.3% - Nest Successn/a7.2%0.8%6.9%

14 Comparison of Nest Success Estimation Methods Method Pooled Apparent - Hatch Success15.0%26.8%25.9%32.8% - Nest Success5.0%15.5%18.8%17.9% Mayfield - Hatch Success0.6%20.0%12.9%18.4% - Brood Success0.3%35.8%57.1%50.0% - Nest Success0.0%7.2%7.4%9.2% Program MARK - Hatch Success7.4%20.0%14.0%16.7% - Brood Successn/a36.2%57.3%41.3% - Nest Successn/a7.2%0.8%6.9%

15 Hatch Success Models Program MARK

16 Brood Success Models Program MARK

17 Nest Success Rates by Habitat Pooled (2005 – 2006) TotalBeachMarshIslands Hatch Success 16.3%5.5%20.1%34.7% Brood Success 51.3%34.8%53.8%58.0% Nest Success 8.4%1.9%10.8%20.1%

18 Nest Success Rates by Habitat Pooled (2005 – 2006) TotalBeachMarshIslands Hatch Success 16.3%5.5% (19.8% - 1.0%) 20.1% (18.8% %) 34.7% (21.9% %) Brood Success 51.3%34.8% (52.1% - 6.2%) 53.8% (26.9% %) 58.0% (34.4% %) Nest Success 8.4%1.9% (10.3% - 0.1%) 10.8% (5.1% %) 20.1% (7.5% %)

19 Findings

20 Findings Nest success influenced heavily by presence of mammalian predators Nestling survival may be correlated with interaction between hatch date and gull density High annual variability in nest success across habitats –Annual variability in flooding –Annual changes in mammal density

21 Development Effect What about the effects of coastal development?

22 Disturbance Effect And human disturbance?

23 CART Modeling Site-level explanatory model –Habitat characteristics measured in field –GIS layers for development/land use Landscape-level predictive model –GIS layers only (surrogates) –Test model with statewide surveys on barrier islands and in back bays

24 Future Research Modeling Survival in MARK –Increase Banded Population in NJ –Coordinate Band Resighting Efforts with AMOY Working Group Modeling Nest Success in MARK –Refine Nest Monitoring Methods –Datalogs Population Viability Analysis

25 Committee Members: Julie Lockwood, Rutgers University Rick Lathrop, Rutgers University David Ehrenfeld, Rutgers University David Drake, University of Wisconsin Field Techs: Mike Ferguson Steve Grodsky Patti Rendo Sheryl Senczakiewicz Acknowledgements NJDFW - Endangered & Nongame Species Program: Dave Jenkins Todd Pover Chris Kisiel Kathy Clark Larry Niles, Conserve Wildlife USFWS - Forsythe National Wildlife Refuge NJ Division of Parks & Forestry – Island Beach State Park The American Oystercatcher Working Group Humphrey Sitters, International Wader Study Group Jim Merritt, NJDFW - Program Director, Sedge Island Natural Resource Education Center David Lapuma, Rutgers University

26 Kristen AND Kristen for spending countless hours in the field with me over the past two years watching oystercatchers


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