Island Habitats for Wading Birds A criticallylimiting resource in the predatorrich northeast coastal zone Katharine C. Parsons Manomet Center for Conservation Sciences
Short-distance migrants Most east coast birds winter in US southeast and Caribbean Some northern individuals winter in New England Return to breeding sites in early spring
Herons return to nest-sites used successfully in the past
Many species are highly colonial
Clutch size ranges from 3-5 eggs
Wading birds commute to foraging habitats within 20 km of colony
Nestling production reflects wetland quality
Common wading birds in NYH
Heron populations grow in NYH 2500 2000 Total Nests 1500 1000 500 0 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 Year
Passage of Clean Water Act reduces raw sewage inputs to harbor
Aquatic food chain re-established in inner harbor waterways
Inner harbor islands colonized
North Brother Is--1989 South Brother Is--1987 Shooters Is--1974 Prall s Is--1982 Isle Meadows--1988
Partnerships developed to study and conserve herons
5 4 3 1986 1987 1988 1989 1990 1991 1992 1993 2 Mean Egg Production 2Mean Egg Production 5 4 3 1986 1987 1988 1989 1990 1991 1992 1993 5 4 3 2 5 4 3 2 1986 1987 1988 1989 1990 1991 1992 1993 1986 1987 1988 1989 1990 1991 1992 1993 Mean Egg Production Mean Egg Production
Oil spills of 1990 killed wintering birds and degraded tidal wetlands
3 Oil Spill 2 1 1986 1987 1988 1989 1990 1991 1992 1993 3 2 1 0 Oil Spill 1986 1987 1988 1989 1990 1991 1992 1993 0 Mean Nestling Production Mean Nestling Production 3 2 1 0 Oil Spill 1986 1987 1988 1989 1990 1991 1992 1993 3 2 1 0 Oil Spill 1986 1987 1988 1989 1990 1991 1992 1993 Mean Nestling Production Mean Nestling Production
Manomet s regional wading bird research and conservation projects Breeding Foraging Toxicology Management Coalitions
Hatching success higher in urban estuaries 100 100 Hatching Success 90 80 70 Hatching Success 90 80 70 60 DEL NYH NAN BOS 60 DEL NYH NAN BOS 100 100 Hatching Success 90 80 70 Hatching Success 90 80 70 60 DEL NYH NAN BOS 60 DEL NYH NAN BOS
Fledging success higher in urban estuaries Fledging Success 100 80 60 40 20 0 DEL NYH NAN BOS Fledging Success 100 80 60 40 20 0 DEL NYH NAN BOS 100 100 Fledging Success 80 60 40 20 0 DEL NYH NAN BOS Fledging Success 80 60 40 20 0 DEL NYH NAN BOS
Egg inviability urban estuaries; Egg predation non non-urban estuaries Inviab le 46% Predated 54% In vi abl e 71% Pr ed ated 29% NYH NYH Inviable 35% Inviable 28% Pre dated 65% DEL Predated 72% DEL
Starve d 52% Predate d 48% Starved 53% Predated 47% NYH NYH Nestling predation non non-urban estuaries Starved 26% Starved 22% Predated 74% DEL Pre dated 78% DEL
Why are predators having such a devastating impact in non-urban heronries? Predator Nests/1000 Heron Nests 20 16 12 8 4 0 DEL NYH
Manomet s toxicological studies in non-urban estuaries show pesticide exposure in wading birds
Wading birds are exposed to new generation (post-ddt) insecticides through skin through diet
Pesticides detected in heron diet and on skin Diet dimethoate, parathion, malathion, methamidophos, chlorpyrifos Skin phorate, naled
Neurotoxic pesticides deplete key enzymes in exposed birds Mean cholinesterase levels are 10-20% lower in non-urban estuaries than in New York Harbor
Low cholinesterase increases vulnerability to predators
Predators cause nest-site and colony-site abandonments Number of Nests 6000 5000 4000 3000 2000 1000 0 49 51 59 67 68 69 70 71 75 76 77 78 79 83 85 95 Stone Harbor New Jersey s largest heronry Number of Nests 18000 15000 12000 9000 6000 3000 0 1964 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 Pea Patch Island largest heronry on the east coast
Colony-site selection since 1970s increases isolation of nesting birds 1970s mainland 53% island 47% mainland 11% 1990s island 89%
Wading birds actively colonize urban estuaries mid-1970s to mid-1990s Total Nests 2500 2000 1500 1000 New York Harbor 15% increase 500 0 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 Year N Breeders 2500 2000 1500 1000 500 Boston Harbor 114% increase 0 1977 1984 1994
Wading birds move to urban estuaries Baltimore Harbor New York Harbor Boston Harbor Island rich Pesticide use minimal
NYH inner harbor wading bird populations have declined since mid-1990s 2500 2000 Total Nests 1500 1000 500 0 77 79 81 83 85 87 89 91 93 95 97 99 01 03
Inner harbor islands abandoned; Outer harbor islands colonized Goose Is--stable N. Brother Is decline? Huckleberry Is--decline S. Brother Is--stable x Canarsie Pol--increase x x Hoffman Is--stable
Productivity in inner harbor not sustainable SNEG BCNH CAEG 0 1 2 3 4 Fledglings/nest
Low productivity results from industrial contaminants Concentration (ppm) 8 6 4 2 0 Regional NYH COD BOS DEL NAN PCBs Concentration (pg/g) 200 150 100 50 0 Coastal NY Newark Bay Outer Harbor E. Long Is dioxins
Total NY/NJ Harbor Estuary populations peaked in mid-1990s 2500 2000 N nests 1500 1000 500 0 77 79 81 83 85 87 89 91 93 95 97 99 01 03
Boston Harbor populations decimated 2500 2000 N Breeders 1500 1000 500 0 1977 1984 1994 2002
Coastal wading birds declining regionally N Breeding Birds 14000 12000 10000 8000 6000 4000 2000 0 SNEG BCNH 1970s 1980s 1990s 2000s
In non-urban estuaries, wading birds exposed to pesticides Neurotoxins increase vulnerability to predators Non-urban heronries abandoned due to high predation rates Wading birds colonize New York Harbor In NYH and other urban estuaries, wading birds exposed to industrial contaminants Productivity below sustainable level for more than a decade Adults in population not replaced In region, total wading bird populations decline by nearly 40%
Waterbird Conservation BCR 14 PBCR 79 # BCR 30 PBCR 78 Mid-Atlantic/New England/Maritimes Waterbird Conservation Working Group
NYH clean-up efforts Toxics Work Group -Contaminants Assessment and Reduction Project Dredged Material Management Integration Work Group Habitats Work Group
Protection from pesticides Food Quality Protection Act National Pesticides Coalition Research needs more apparent Wildlife-Human linkages
Manomet s continuing commitment Pesticide Best Management Practices Wildlife/Human Health Coalition Waterbird Conservation Toxics monitoring
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