Great Egret Roosting Dynamics

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1 Great Egret Roosting Dynamics in Suburban NYC Mike Allen 1, Nellie Tsipoura 1, Susan Elbin 2, and Chip Weseloh 3 1 NJ Audubon, 2 NYC Audubon, 3 Canadian Wildlife Service

2 Harbor Herons Harbor Herons, herons, egrets, and ibises nesting on islands in the NY/NJ Harbor, have been hailed as signs of improved environmental quality and biodiversity in the Harbor Bight region.

3 Harbor Herons Harbor Heron rookeries are located on islands in the NY/NJ Harbor and have been studied by NYC Audubon since the 70s Data have been used in conservation and management plans for the NY/NJ Harbor.

4 Harbor Herons Birds fly from island nesting colonies to other areas where they forage Use of foraging habitat and post breeding movements studied by NJA and NYCA 2008 (with citizen science effort) Data have been used in conservation and management plans for the NY/NJ Harbor.

5 Harbor Herons Surveys show increases in numbers of Egrets foraging in the NJ Meadowlands and Raritan River/Bay later in the season These birds are not using the areas immediately near rookeries anymore Where do they spend the night???

6 Roost study NJ Audubon and NYC Audubon

7 What is a roost? Communal sleeping area Sizes vary Roosts ranging from 1 to 700+ egrets Often mixed species Mainly egrets, cormorants, and night herons Used perennially One in NJ active since at least since the 1970s (Rich Kane, pers. comm.).

8 Why bother with them? Important part of life cycle Safety Foraging (information center) Post breeding / pre migration refueling John Brzorad s tracked birds Useful as a monitoring tool? Locate preferred foraging areas Late season populations, migration phenology Sensitive to disturbance Abandonment, similar to colonies

9 Photo by Allen Woodliffe Where are they and how are they being used?

10 Methods: Finding Roosts Roost Blitz Asked Harbor Herons foraging survey volunteers to keep an eye out Scouted by plane and boat Reached out to birders, professionals

11 Methods: Monitoring Based on Chip W s Ontario protocol Visit weekly if possible Count arrivals/departures in 5 min intervals Evening: 60 min before sunset until dark Morning: 30 min before sunrise until all birds leave Counts by staff and volunteers Liv Vreeland, Mike Dixon, Debbie Schmidt, Dan Morley and others

12 Results

13 NYC and NJ Audubon Volunteer Roost Seekers Joe O Sullivan Catherine Barron Jeff and Lynn Krauss Mike Dixon Liz Vreeland Debbie Schmidt Dan Morley Jim Ceravolo Bill Schultz Pat and Mike Hilliard George Pitcher Kirk Weber Ernie Lowenfels Lorraine Ninski Ian Garrison Jorge Monteagudo Jim Wright Lena Kelly Mike Britt Charlene Burke Tom Shinskey Lene De Coursin Camille Gutmore Jerry Golub Becky James Mike Fedosh Joe Fischetti (pilot) LightHawk (non profit) Eileen and Stanley Smith Steve Gruber John Tyler Hugh Carola Regina Sieben Eden Tessa Brian Palestis Mike Newhouse Don Smith Special thanks to Laura Stern and Tom Smith for handling all the data!

14 Recent Roost Finders Joan Tell (Lincoln Park Comm. Lake) Eden Tessa (Raritan Center) Linda Stehlik (Shadow Lake) Lene Jacobs (Degnan Park) Maureen Conery (Rumson Pond) Don Smith (Mehrhof Pond) Roost Monitors Liz Vreeland (Lake Matawan) More needed!

15 15 Known Roosts Meadowlands: 4 Kearny Marsh, Laurel Hill, Clay Ave., Merhoff Pond Raritan Bayshore: 6 Cheesequake Creek, Natco Lake, Lake Matawan, Shadow Lake, Raritan Center, Rumson Pond Bayonne / Jersey City: 2 Lefante Walkway, Lincoln Park West In between : 3 Degnan Park (W. Orange), Lincoln Park Community Lake (Lincoln Park), Linden Hawk Rise Pond

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17 Roost Characteristics (n = 15) Substrate live trees (13), dead trees (1), structure (1) Relation to water lake/pond (12), flowing water (3) Closest together: 2.5 km Photo: M. Allen Photo: Eden Tessa

18 Species Composition In addition to Great Egrets: Black crowned Night Heron Double crested Cormorant Snowy Egret Cormorants outnumber Great Egrets at the Lake Matawan roost Snowy Egrets at the Kearny Roost sleep Separately from the Greats. Great Egrets at the Kearny Roost.

19 Roost Profiles

20 New Roosts in 2014 One large and one small. Mehrhof Pond, Meadowlands Linden Landfill

21 Kearny Roost The largest roost, it has been in use since at least the 1970s! (R. Kane, pers. comm.)

22 Lake Matawan Roost Our 2 nd largest roost, in use for at least several years. (L. Vreeland, pers. comm.)

23 Seasonal Patterns Seasonal Patterns Roost 11 evening counts, all starting min before sunset 4 morning counts, all starting min before sunrise

24 Seasonal Patterns Seasonal Patterns Roost 11 evening counts, all starting min before sunset 4 morning counts, all starting min before sunrise

25 N = 10 observations of roosts with >40 birds. Timing of Morning Roost Departure

26 Timing of Morning Roost Departure

27 Things to Ponder What causes variation in occupancy among and within roosts? Variation in food resources? Who are these birds? % of juveniles, migrants Summer usage Is there a roost in NYC? A challenge! Goethal s Pond?

28 Questions?