NYC Audubon Harbor Herons Program 31st Annual Survey Wading Bird, Cormorant, and Gull Nesting Activity in 2015
Tod Winston1, Susan Elbin1, and Elizabeth Craig1,2 1) NYC Audubon & 2) Cornell University
Harbor Herons Annual Subcommittee Meeting: Greater NY/NJ Harbor Colonial Waterbirds Working Group
December 3, 2015 Acknowledgements
Study PI: Susan Elbin Our past survey leader: Liz Craig Numerous collaborators and volunteers: • Fieldwork! Annie Barry, John Burke, Liz Craig, Marisa Dedominicis, Melanie Del Rosario, Greg Elbin, Mike Feller, Laura Francoeur, Stefan Guelly, Tom Heinimann, Sarah Heintz, Jeff Kolodzinski, Debra Kriensky, Dave Künstler, Andrew Maas, Melissa Malloy, Ritamary McMahon, Melissa Murgittroyd, Ellen Pehek, Don Riepe, Erica Santana, Susan Stanley, Alex Summers
• Permits and administration! George Frame, Dave Taft, Kathy Garofalo, Ellen Pehek, Hanem Abouelezz, Susan Stanley, Marit Larson, Joe Pane
• NYC Parks and Recreation • National Park Service • NJ Audubon • Huckleberry Indians • American Littoral Society/Jamaica Bay Guardian Survey Area May 18-29, 2015 Wading birds of the NY/NJ Harbor Islands
10 species of long-legged waders: 7 observed in 2015
Great Blue Heron, Area herodias Great Egret, Ardea alba Snowy Egret, Egretta thula Little Blue Heron, Egretta caerulea Tricolored Heron, Egretta tricolor Cattle Egret, Bubulcus ibis Green Heron, Butorides virescens Black-Crowned Night-Heron, Nycticorax nycticorax Yellow-Crowned Night-Heron, Nyctanassa violacea Glossy Ibis, Plegadis falcinellus Other Nesting Species Colonial Nesters Double-Crested Cormorant, Phalacrocorax auritus
Herring Gull, Larus argentatus
Great Black-Backed Gull, Larus marinus
Single Nesters Waterfowl: Canada Goose, Mute Swan, American Black Duck, Mallard, Gadwall
American Oystercatcher
Spotted Sandpiper
Passerine sp.
Methods
• May 18-29, 2015 • Travel to islands by boat • Conduct ground surveys of nesting birds using 1-3 teams of surveyors – One person to record data – One person to observe nest content – One person to navigate through colony • When possible, we identify each nest to species, and record nest content and nesting substrate
Results
• By Species • By Island
http://www.dancingotter.ca
Wading Bird Nesting Activity – 1982-2015
Harbor Heron Populations, 1982-2015 2500
GREG 2000 CAEG SNEG
1500 BCNH YCNH LBHE Population 1000 GLIB GRHE 500 TRHE UNID TOTAL 0 Fluidity in Colony Placement Over 30+ Years
Nesting Island Trends, All Waders 2500
Pralls
Shooters 2000 I. of Meadows
South Brother
1500 North Brother
Little Egg
Elders E. Axis Axis Title 1000 Subway
Canarsie
Goose 500 Huckleberry
Hoffman
0 Mill Rock 1982 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014
Black-Crowned Night-Heron
Harbor Heron Populations, 1982-2015 1600
1400 GREG 1200 CAEG
1000 SNEG
BCNH 800 YCNH
Population LBHE 600 GLIB 400 GRHE TRHE 200 UNID
0 Black-Crowned Night-Heron
Nesting Island Trends, BCNH 1000
Little Egg 900
Elders E. 800
Subway 700
Canarsie
600
Goose 500
Nesting Pairs Huckleberry 400
Hoffman 300
Mill Rock 200
South Brother 100
North Brother 0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Great Egret
Harbor Heron Populations, 1982-2015 700
600
GREG 500 CAEG
SNEG 400 YCNH
300 LBHE Population GLIB 200 GRHE TRHE 100 UNID
0 Great Egret
Nesting Island Trends, GREG 600
500
Little Egg 400 Elders E.
Subway Canarsie 300 Goose
Nesting Pairs Huckleberry
200 Hoffman Mill Rock South Brother 100
0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Snowy Egret
Harbor Heron Populations, 1982-2015 700
600
GREG 500 CAEG
SNEG 400 YCNH
300 LBHE Population GLIB 200 GRHE TRHE 100 UNID
0 Snowy Egret
Nesting Island Trends, SNEG 350
300
250 Little Egg Elders E.
Subway 200 Canarsie Goose 150 Nesting Pairs Huckleberry Hoffman 100 Mill Rock South Brother
50
0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Glossy Ibis
Harbor Heron Populations, 1982-2015 700
600
GREG 500 CAEG
SNEG 400 YCNH
300 LBHE Population GLIB 200 GRHE TRHE 100 UNID
0 Glossy Ibis
Nesting Island Trends, GLIB 400
350
300
250 Elders E.
Subway
200 Canarsie Goose Nesting Pairs 150 Hoffman South Brother 100
50
0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Other Waders in 2015
• Little Blue Heron: 6n • Tricolored Heron: 2n • No Cattle Egret (last pair seen in 2010) • No Green Heron on islands – Breeding in Prospect Park and on S.I.? Anywhere else? • No Great Blue Heron on islands – Breeding in Clove Lakes Park, S.I. Anywhere else? Other Wader Species
Harbor Heron Populations, 1982-2015 300
250
200
CAEG YCNH 150 LBHE Population GRHE 100 TRHE
50
0
Yellow-Crowned Night-Heron
Nesting Island Trends, YCNH 70
60
50 Red Fern
Subway 40 Canarsie Goose 30 Nesting Pairs Hoffman Mill Rock
20 South Brother
10
0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Redfern Houses, Far Rockaway, NY
50 YCNH nests -slightly increasing in recent years
YCNH Gaining a Foothold in the Five Boroughs
• Governors Island (2n) • Bushwick Housing Project (~10n) • Sheepshead Bay (~6n) • Throggs Neck (~4n) • SI? • Elsewhere?
Double-Crested Cormorant vs. Waders Double-Crested Cormorant
Nesting Island Trends, DCCO 2000
1800
1600 Elders W. 1400 U-Thant Swinburne
1200 Elders E.
1000 Canarsie Goose Nesting Pairs 800 Huckleberry
600 Hoffman Mill Rock 400 South Brother
200
0 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Other Colonial Waterbirds - 2015
# Increase or decrease Increase or decrease 2015 since 2014 interim since 2010 Species Pairs* survey comprehensive survey
HERG 169 Decreased from 223 Decreased from 397
GBBG 87 Decreased from 169 Decreased from 144
* Pairs determined by nest or adult count on islands excluding Jamaica Bay (see USDA report)
Huckleberry Island – 10 acres With Dave Künstler
• Decline since high of 140 nests in 2001 • 3 current GREG and 2 BCNH nests identified but no adults sighted. 2 inactive SNEG nests from prior years – 1 GREG nest with broken eggs beneath it
• DCCO also declining in 4/5 last years (-49% from 2014)
• Potential factors in decline: – Mammalian predators (raccoon tracks found) – Human disturbance, although sanctioned access is limited Goose Island – 1 acre With Dave Künstler
• Total =0 active nests Second year of no nesting after 2013 count of 87 nests, almost all predated • Evidence of rats (being treated by Parks?) • Evidence of human disturbance • New signage
North Brother – 19 acres
• Eighth consecutive year of no evidence of colonial waterbird nesting activity • Empty since only 15n counted in 2007, down from high of 277 in 1995) • Recent habitat enhancement work • Talk of developing island South Brother – 12 acres • Sp. Composition: BCNH, SNEG, GREG, YCNH (GLIBs, which nested in low numbers since 1992, have not been seen since 2011)
• Second largest wading bird colony in 2015
• Total = 270 (-32% from 2014, slightly below 2013 count of 286 pairs)
• Decline over 2014 primarily due to 51% reduction in BCNH count
• Cormorant numbers up 129% from 2014
• YCNH down since 2014 but continue to nest in cormorant colony
Mill Rock – 4 acres
• First pairs found in 2004 • Sp. Composition: BCNH, GREG, a few SNEG • Total = 115 (+20% from 2014, but down from high of 203 in 2012) • DCCO total = 49n (+96% over 2014) U Thant – 0.75 acres
• 40n DCCO, about the same from 2008-2015 (DCCO, HERG and GBBG)
Hoffman Island – 10 acres • Largest wading bird colony from 2009-2015
• Sp. Composition: BCNH, GREG, SNEG, GLIB, LBHE, (YCNH). Second most diverse colony in 2015, hosting 5 wader species
• Total = 504n, down from pre-Sandy high of 824 in 2011, but stable over last 15 years. 54% reduction in GLIB over 2014
• Cormorant numbers down just slightly in 2015 (-6%)
Swinburne Island – 4 acres
• Sp. Composition: DCCO, (BCNH) • 281n in 2015, down 11% compared to 2014 but stable across last decade
Canarsie Pol – 220 acres
• One of the most diverse and largest colonies in NY Harbor from 1999-2011 • Total = 0 pairs (- from 497 in 2010) • A proportion of birds from CP likely moved to other JB islands like Subway and Elder’s point marsh • Predators (mammal and avian) likely played a major role in collapse as they have at other colonies in Jamaica Bay and beyond (Huckleberry, Goose, and others?). • Signage? Camera traps?
Subway Island – 40 acres
• Sp. Composition: BCNH, GREG, SNEG, GLIB • No DCCOs • Total = 197 pairs, -36% over 2014 (third year of decline since high of 373 in 2013, on this new and vulnerable colony, established in 2007) • Numbers of all wader species down since 2014, but GLIB numbers greatest decline at 62%
Elder’s Point East Marsh • USACE marsh restoration, first nesting pairs (18) in 2010
• Most diverse island at 6 species of waders; distinct habitat
• Sp. Composition: SNEG, BCNH, GREG, GLIB, LBHE, TRHE
• Total = 158n, up 49% over 2014
• Cormorants = 208n (up 16% over 2014)
Challenges in methodology 1. Develop a repeatable method for surveying impenetrable/sensitive habitats – Canarsie Pol – Hoffman and South Brother (grid system) 2. Implement a habitat assessment protocol 3. Monitor productivity to gain better understanding of population statuses 4. Monitor gull population Challenges • Habitat – bittersweet, porcelainberry, kudzu – attractive nest structure vs long-term degradation of nesting habitat – South Brother is a good example – Storms !
• Asian Longhorned Beetle – 2007: confirmed on Prall’s Is in March & ~3,500 host trees removed in April, an additional 8,000 at Old Place & Saw Mill, SI – Preferred wading bird nesting trees overlap w/ ALB host trees
• Predation – Mammals (Ruffle Bar, CP, Huckleberry, & Goose)
Kenneth Law USDA-APHIS – Birds (owls, fish crows, etc.)
• Human disturbance • Contaminants: Plastic (microbeads), marine floatables • Decreasing # of viable islands?
Thank You!!!
Mill Rock – 3 acres
• 2014 Total = 96n (down from 113 in 2013) • Nesting habitat not physically damaged by Sandy
Shooter’s Island – 48 acres
• DCCO = 10n - western shore on remnants of drydocks Prall’s Island – 80 acres
• No colonial waterbird nesting activity
Isle of Meadows – 101 acres
• Not surveyed in 2013
Photos: Alexander Summers, NYC Parks - NRG Aids to navigation Raritan Bay, AK/KVK
• DCCO = 51n observed in the Kill Van Kull, Arthur Kill, northwestern Raritan Bay, and Newark Bay (stable)