Title Page Evaluating American Oystercatcher Productivity: A Comparison of Nest Success Estimation...

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

Transcript of Title Page Evaluating American Oystercatcher Productivity: A Comparison of Nest Success Estimation...

Title Page

Evaluating American Oystercatcher Productivity: Evaluating American Oystercatcher Productivity: A Comparison of Nest Success Estimation MethodsA Comparison of Nest Success Estimation Methods

Photo: www.birdsbykim.com

Tom Virzi, Ph.D. CandidateTom Virzi, Ph.D. Candidate

Department of Ecology, Evolution Department of Ecology, Evolution and Natural Resourcesand Natural Resources

Rutgers, The State University of NJRutgers, The State University of NJ

Research ObjectivesResearch 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: www.birdsbykim.com

• 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

HypothesesHypotheses

Photo: www.birdsbykim.com

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

MethodsMethods

Nest Success Nest Success Estimation MethodsEstimation Methods

• Apparent Nest Success– Biases High

• Mayfield Method– Daily Survival Probabilities

• Program MARK– Information Theoretic Approach (AIC)– Covariates

Nest Success TermsNest 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)

NJ AMOYs

North Coast – 8 Pairs

Central Coast – 25 Pairs

South Coast – 35 Pairs

Beach Breeding Beach Breeding Pairs in New JerseyPairs in New Jersey

Study Sites

Sites selected over a gradient of human

disturbance

Public Use

Beach Closures

ORV

Use

Island Beach

State Park

High Minimal Area

All Year

Forsythe NWR

Holgate Division

Low Entire Beach

Winter Only

Stone Harbor Point

Med Large Area

Winter Only

5

18

10

IB

HG

SH

Holgate

HolgateHolgate

Beach – 23 Pairs

Marsh – 3 Pairs

Island – 1 Pair

Total Pairs – 27

(Beach 2005 – 18)

Stone Harbor

Stone HarborStone Harbor

Beach – 19 Pairs

Marsh – 11 Pairs

Island – 8 Pairs

Total Pairs – 38(Beach 2005 – 20)

Island Beach

Island BeachIsland Beach

Beach – 5 Pairs

Marsh – 11 Pairs

Island – 25 Pairs

Total Pairs – 41(Beach 2005 – 5)

ResultsResults

Comparison of Nest Success Estimation MethodsComparison of Nest Success Estimation Methods

Method 2004 2005 2006 Pooled

Apparent

- Hatch Success 15.0% 26.8% 25.9% 32.8%

- Nest Success 5.0% 15.5% 18.8% 17.9%

Mayfield

- Hatch Success 0.6% 20.0% 12.9% 18.4%

- Brood Success 0.3% 35.8% 57.1% 50.0%

- Nest Success 0.0% 7.2% 7.4% 9.2%

Program MARK

- Hatch Success 7.4% 20.0% 14.0% 16.7%

- Brood Success n/a 36.2% 57.3% 41.3%

- Nest Success n/a 7.2% 0.8% 6.9%

Comparison of Nest Success Estimation MethodsComparison of Nest Success Estimation Methods

Method 2004 2005 2006 Pooled

Apparent

- Hatch Success 15.0% 26.8% 25.9% 32.8%

- Nest Success 5.0% 15.5% 18.8% 17.9%

Mayfield

- Hatch Success 0.6% 20.0% 12.9% 18.4%

- Brood Success 0.3% 35.8% 57.1% 50.0%

- Nest Success 0.0% 7.2% 7.4% 9.2%

Program MARK

- Hatch Success 7.4% 20.0% 14.0% 16.7%

- Brood Success n/a 36.2% 57.3% 41.3%

- Nest Success n/a 7.2% 0.8% 6.9%

Hatch Success ModelsHatch Success ModelsProgram MARKProgram MARK

Delta AICc ModelModel AICc AICc Weights Likelihood #Par Dev{Year + Habitat + Mammal + Year.Habitat} 575.65 0.00 0.53 1.00 9 557.57{Year + Habitat + Mammal + Year.Habitat + Year.Mammal} 577.64 1.99 0.20 0.37 11 555.51{Year + Habitat + Mammal + Disturb + Year.Habitat} 577.64 1.99 0.20 0.37 10 557.54{Year + Habitat + Mammal + Disturb + Year.Habitat + Year.Mammal} 579.61 3.96 0.07 0.14 12 555.47{Year + Habitat + Mammal + Year.Mammal} 599.84 24.19 0.00 0.00 8 583.77{Year + Mammal + Disturb + Year.Mammal} 600.14 24.49 0.00 0.00 7 586.09{Mammal} 601.50 25.85 0.00 0.00 2 597.50{Year + Habitat + Mammal + Disturb + Year.Mammal} 601.85 26.20 0.00 0.00 9 583.77{Habitat + Mammal} 602.04 26.39 0.00 0.00 4 594.02{Mammal + Disturb} 602.55 26.90 0.00 0.00 3 596.54{Year + Mammal} 603.17 27.53 0.00 0.00 4 595.16{Year + Habitat + Mammal} 603.38 27.73 0.00 0.00 6 591.34{Habitat + Mammal + Disturb} 603.90 28.25 0.00 0.00 5 593.87{Year + Mammal + Disturb} 604.51 28.86 0.00 0.00 5 594.48{Year + Habitat + Mammal + Disturb} 605.36 29.71 0.00 0.00 7 591.31{Year + Habitat + Year.Habitat} 608.39 32.74 0.00 0.00 8 592.32{Year + Habitat + Disturb + Year.Habitat} 610.40 34.75 0.00 0.00 9 592.32{Habitat} 631.95 56.31 0.00 0.00 3 625.94{Habitat-Beach} 631.95 56.31 0.00 0.00 3 625.94{Habitat-Marsh} 631.95 56.31 0.00 0.00 3 625.94{Habitat-Island} 631.95 56.31 0.00 0.00 3 625.94

Brood Success ModelsBrood Success ModelsProgram MARKProgram MARK

Delta AICc ModelModel AICc AICc Weights Likelihood #Par Dev{Year + Habitat + Mammal + Year.Habitat} 187.33 0.00 0.22 1.00 7 173.26{Mammal} 189.35 2.02 0.08 0.36 2 185.34{Year + Habitat + Mammal + Year.Habitat + Year.Mammal} 189.36 2.02 0.08 0.36 8 173.26{Year + Habitat + Year.Habitat} 189.70 2.37 0.07 0.31 6 177.64{Year + Mammal} 190.43 3.09 0.05 0.21 3 184.41{Gull + Mammal} 190.63 3.30 0.04 0.19 3 184.61{Year} 190.82 3.49 0.04 0.18 2 186.81{Year-2005} 190.82 3.49 0.04 0.18 2 186.81{Year-2006} 190.82 3.49 0.04 0.18 2 186.81{Constant DSR} 191.03 3.70 0.03 0.16 1 189.03{Mammal + Disturb} 191.11 3.77 0.03 0.15 3 185.09{Year + Gull + Mammal} 191.67 4.33 0.03 0.11 4 183.64{Year + Mammal + Disturb} 192.27 4.93 0.02 0.08 4 184.24{Year + Mammal + Year.Mammal} 192.29 4.95 0.02 0.08 4 184.26{Gull + Mammal + Disturb} 192.63 5.30 0.02 0.07 4 184.60{Year + Gull} 192.65 5.31 0.02 0.07 3 186.63{Year + Disturb} 192.78 5.44 0.01 0.07 3 186.76{Habitat + Mammal} 192.91 5.57 0.01 0.06 4 184.88{Gull} 192.95 5.62 0.01 0.06 2 188.94{Disturb} 192.97 5.64 0.01 0.06 2 188.96{Habitat} 193.26 5.93 0.01 0.05 3 187.25

Nest Success Rates by HabitatNest Success Rates by HabitatPooled (2005 – 2006)Pooled (2005 – 2006)

Total Beach Marsh Islands

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%

Nest Success Rates by HabitatNest Success Rates by HabitatPooled (2005 – 2006)Pooled (2005 – 2006)

Total Beach Marsh Islands

Hatch Success

16.3% 5.5%(19.8% - 1.0%)

20.1%(18.8% - 21.6%)

34.7%(21.9% - 54.0%)

Brood Success

51.3% 34.8%(52.1% - 6.2%)

53.8%(26.9% - 63.3%)

58.0%(34.4% - 69.4%)

Nest Success

8.4% 1.9%(10.3% - 0.1%)

10.8%(5.1% - 13.7%)

20.1%(7.5% - 37.5%)

FindingsFindings

FindingsFindings

• 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

Development EffectWhat about the effects of coastal development?

Disturbance Effect

And human disturbance?

CART ModelingCART 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

Future ResearchFuture 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

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

AcknowledgementsAcknowledgements

NJDFW - Endangered & Nongame Species Program:• Dave Jenkins• Todd Pover• Chris Kisiel• Kathy Clark

Larry Niles, Conserve WildlifeUSFWS - Forsythe National Wildlife RefugeNJ Division of Parks & Forestry – Island Beach State ParkThe American Oystercatcher Working GroupHumphrey Sitters, International Wader Study GroupJim Merritt, NJDFW - Program Director, Sedge Island

Natural Resource Education CenterDavid Lapuma, Rutgers University

KristenAND

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