nyc audubon harbor herons program 31st annual … · canarsie pol – 220 acres • one of the most...
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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
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
Acknowledgements
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
0
500
1000
1500
2000
2500
Po
pu
lati
on
Harbor Heron Populations, 1982-2015
GREG
CAEG
SNEG
BCNH
YCNH
LBHE
GLIB
GRHE
TRHE
UNID
TOTAL
Fluidity in Colony Placement Over 30+ Years
0
500
1000
1500
2000
2500
1982 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014
Axi
s Ti
tle
Nesting Island Trends, All Waders
Pralls
Shooters
I. of Meadows
South Brother
North Brother
Little Egg
Elders E.
Subway
Canarsie
Goose
Huckleberry
Hoffman
Mill Rock
Black-Crowned Night-Heron
0
200
400
600
800
1000
1200
1400
1600
Po
pu
lati
on
Harbor Heron Populations, 1982-2015
GREG
CAEG
SNEG
BCNH
YCNH
LBHE
GLIB
GRHE
TRHE
UNID
Black-Crowned Night-Heron
0
100
200
300
400
500
600
700
800
900
1000
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Ne
stin
g P
airs
Nesting Island Trends, BCNH
Little Egg
Elders E.
Subway
Canarsie
Goose
Huckleberry
Hoffman
Mill Rock
South Brother
North Brother
Great Egret
0
100
200
300
400
500
600
700
Po
pu
lati
on
Harbor Heron Populations, 1982-2015
GREG
CAEG
SNEG
YCNH
LBHE
GLIB
GRHE
TRHE
UNID
Great Egret
0
100
200
300
400
500
600
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Ne
stin
g P
airs
Nesting Island Trends, GREG
Little Egg
Elders E.
Subway
Canarsie
Goose
Huckleberry
Hoffman
Mill Rock
South Brother
Snowy Egret
0
100
200
300
400
500
600
700
Po
pu
lati
on
Harbor Heron Populations, 1982-2015
GREG
CAEG
SNEG
YCNH
LBHE
GLIB
GRHE
TRHE
UNID
Snowy Egret
0
50
100
150
200
250
300
350
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Ne
stin
g P
airs
Nesting Island Trends, SNEG
Little Egg
Elders E.
Subway
Canarsie
Goose
Huckleberry
Hoffman
Mill Rock
South Brother
Glossy Ibis
0
100
200
300
400
500
600
700
Po
pu
lati
on
Harbor Heron Populations, 1982-2015
GREG
CAEG
SNEG
YCNH
LBHE
GLIB
GRHE
TRHE
UNID
Glossy Ibis
0
50
100
150
200
250
300
350
400
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Ne
stin
g P
airs
Nesting Island Trends, GLIB
Elders E.
Subway
Canarsie
Goose
Hoffman
South Brother
• 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 Waders in 2015
Other Wader Species
0
50
100
150
200
250
300
Po
pu
lati
on
Harbor Heron Populations, 1982-2015
CAEG
YCNH
LBHE
GRHE
TRHE
Yellow-Crowned Night-Heron
0
10
20
30
40
50
60
70
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Ne
stin
g P
airs
Nesting Island Trends, YCNH
Red Fern
Subway
Canarsie
Goose
Hoffman
Mill Rock
South Brother
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
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Ne
stin
g P
airs
Nesting Island Trends, DCCO
Elders W.
U-Thant
Swinburne
Elders E.
Canarsie
Goose
Huckleberry
Hoffman
Mill Rock
South Brother
Other Colonial Waterbirds - 2015
Species
# 2015 Pairs*
Increase or decrease since 2014 interim survey
Increase or decrease since 2010 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) – Birds (owls, fish crows, etc.)
• Human disturbance • Contaminants: Plastic (microbeads),
marine floatables • Decreasing # of viable islands?
Kenneth Law USDA-APHIS
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
Photos: Alexander Summers, NYC Parks - NRG
Isle of Meadows – 101 acres
• No colonial waterbird nesting activity
• Not surveyed in 2013
Aids to navigation Raritan Bay, AK/KVK
• DCCO = 51n observed in the Kill Van Kull, Arthur Kill, northwestern Raritan Bay, and Newark Bay (stable)