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The Harbor Herons Monitoring in 2005
by Chris Nagy
NYC Audubon has been monitoring the heron and egret colonies
scattered throughout the City’s waters for over 30 years.
For the past three, NYCA has been conducting an intensive
study investigating the movement patterns of these birds
from their nest sites. The data collection for this study
is conducted almost entirely by dedicated volunteers. For
those interested in our data analysis, follow this link to
our Data Summary document.
The herons in NYC Harbor build their nests on a number of
small uninhabited (by humans) islands. However, wading birds
need to forage in wetland areas, which are usually located in
places other than the nesting colonies. The islands provide
the isolated, vegetated upland the birds need for nesting,
and the foraging grounds provide prey and shallow wetlands
where the birds feed. This sets up a kind of “commuting”
movement pattern, since the birds move back and forth between
the nest colony and the foraging ground. It has been the
primary goal of the Harbor Herons Monitoring Program to
determine which specific wetland areas are used by the birds
of each nesting colony. If these questions are answered, we
can better determine how to protect vital foraging grounds as
well as the nesting areas.
The 2005 season has been a very successful one. For the first
time, NYCA volunteers have monitored the heron islands from all
sides via boat trips provided by our many project partners.
This summer we monitored four colonies:
Hoffman Island, Canarsie Pol, Brothers Islands, and Goose Island.
In 2003 and 2004, we recorded the direction of flight for every
bird leaving or entering the colony. If the birds tended to leave
to or arrive from a particular direction, then we assumed the
foraging grounds were likely somewhere in that
direction. However, the colonies were observed from the shore of
the mainland only, so the far sides of the islands were never seen.
This was a large hole in our dataset, since we could not see if the
birds were flying in these directions.
This season we were able to partner with a number of organizations
and volunteers that gave us the ability to observe the far sides of
these islands. NYCA member Joe Costa took us out on his luxurious
speed boat four times to the east side of Hoffman Island.
The NY Urban Divers took us out on a small outboard to see the
eastern side of the Brothers Island, and provided a fascinating
sunset ride up the Harlem River afterwards. We also partnered this
year with Kingsborough Community College and the City University of
New York, which provided boat trips to Canarsie Pol and three
excellent interns to help us with data collection and analysis as part
of their undergraduate education. At Goose Island, we were given
access to the roof of an adjacent apartment building by the Riverbay
Corporation, which allowed us to see all sides of the island
simultaneously.
We have also been able to monitor birds from the Fuji Film blimp,
which allowed us to follow birds from their colony to the exact
destination wetland. This yields the best data regarding the
colony—foraging ground connections (since we see the exact spot
the birds fly to), but obviously the amount of data we can gather
is limited. However, combined with the shore/boat monitoring, we
can pick out specific wetlands that need to be preserved.
We’ve only recently begun combining our shore and boat data gathered
by our volunteers with the huge potential of the blimp. In July and
August of this year, we’ve noticed that many of the birds of the
Hoffman Island colony head west, southwest, and south. To the
southwest and west there are wetland areas relatively close to the
colony in Staten Island and the adjacent areas of New Jersey. However,
we did not know where the birds heading south might be going; the
closest land directly south from Hoffman is Sandy Hook, NJ, which is
15 – 20 miles away. Sure enough, when we followed one great egret and
one snowy egret southward, they both went to wetland areas located
in Sandy Hook. We’re now paying special attention to this part of
New Jersey in terms of educating landowners and pushing for wetland
conservation and restoration.
NYCA is currently designing a geographic information system (GIS) that will delineate
available foraging areas in New York City and New Jersey, currently known as the Harbor
Herons Habitat Database. Once local wetlands are digitized, the ownership status
(private or public) of each wetland will be determined, and surveys can be planned.
As data on the use of each wetland becomes available, high-use areas will be identified.
These wetlands will then become candidates for establishing protected status and
initiating restoration efforts.
In the future, we hope to develop research and conservation goals for the most
important wetland areas. Future research will include further monitoring of the flight
paths, as well as abundance estimates and habitat quality studies at the foraging areas.
Conservation will focus on maintaining good nesting habitat on the colonies and pushing
for protection and restoration of the foraging areas.
Acknowledgements
Many people and agencies were vital in the success of this project. NYCA would like
to thank the NYC Environmental Fund for funding this Program as well as the Hudson River
Foundation for administering the grant. We would like to thank all of our partners, the
boat captains and their crews, and all the volunteers that helped this season become such
a success. Jeff Frezoco at the Regional Planning Association drew the all-important flight
path map on short notice.
2005 HHMP Volunteers
Name
Allen, Deborah
Armitage, Ron
Barron, Catherine
Blum, Medi
Bogen, Josh
Bogo, Jennifer
Burgess, Martha
Byron, Michelle
Collins, Patty
Condon, Maggie
Correia, Margarida
Corter, Justin
Costa, Joe
Cote, Gaynor
Devi, Swaha
Duffy, Tim
Gilmartin, Brendan
Graham, Bill
Graham, Marge
Greenburg, Peter
Gorobinskaya, Natalia
Intrator, Jack
Klipp, Kirsten
Kunstler, Dave
Levy, Amanda
McCarthy, Kathleen
McCarthy, Regina
Orgel, Celena
Osorio, Michelle
Paci, Sandra
Rugeiro, Leah
Stim, Sasha
Thorson, Alexandra
Trommer, K.C.
Uthaiah, Revathy
Wiley, Scott
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New York University
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CUNY – Queens College
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NYC Parks Dept.
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CUNY – Queens College
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CUNY – Queens College
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Surveying the foraging grounds in NJ (Navasink River) from the blimp
Monitoring Hoffman colony from the boat
Boarding the Fuji Film blimp at Floyd Bennett Field
Over Sandy Hook, following a Great Egret from Hoffman to NJ wetlands
Volunteers on a NYC Audubon-led fieldtrip to see the foraging grounds
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