New York Bird Monitoring Program

Each spring and fall, Neotrpical migratory songbirds travel thousands of miles between their temperate breeding grounds and tropical wintering grounds. Habitats in between in which the birds can rest and quickly restore depleted energy reserves are critical to successful and timely migrations.

The Human Aspect
The major flight paths of migratory birds in the eastern U.S. overlap with one of the most urbanized regions of North America. From Boston to Miami, numerous cities dot the coastline. Urban parks often represent some of the only stopover habitat available to migrating birds in this area.

Threats
As urbanization proceeds, fewer habitats will remain in which migratory songbirds can refuel before continuing their journeys to northern breeding grounds and southern wintering grounds. It is currently uncertain whether the habitats remaining within cities can serve as suitable stopover sites. The densities at which the birds occur in these small parks and the predominance of exotic invasive vegetation may prohibit the birds from adequately gaining body mass in the face of intense competition for limited resources.

WCS Activities
WCS launched The New York Bird Monitoring Program to evaluate New York City’s parks as migratory bird stopover sites. In Spring 2004, researchers began collecting data from migrants in WCS’s own backyard, the Bronx Zoo. This urban park is not only home to WCS’s living collections, but is also a primary stopover site for birds migrating through the New York City area. By banding the birds, monitoring their rates of weight gain, and measuring blood plasma metabolite levels, WCS is able to assess the quality of the habitat as a migratory bird stopover site.

To date, results suggest the Bronx Zoo is indeed an urban stopover site where migrants can adequately gain mass and restore depleted energy reserves. Similar research is needed in additional areas to determine if this site is representative of other urban habitats. In Spring 2007, WCS expanded the Program to include two additional NYC parks as well as two parks in suburban and rural sections of Westchester County for comparison.

Important Next Steps

• Continue monitoring at the Bronx Zoo and other study sites
• Survey arthropod communities to quantify food abundance
• Continue discussions with park management authorities
• Develop formal community outreach and education programs

Publications

Seewagen, C. L. and E. J. Slayton. 2008. Mass changes of migratory landbirds during stopovers in a New York City park. Wilson Journal of Ornithology 120(2):296-303. Request a copy.

Seewagen, C. L. 2008. Lipid content of Nearctic-neotropical migratory passerines killed during stopovers in a New York City park. Northeastern Naturalist 15(1):87-96. Request a copy.

Seewagen, C. L. 2008. An evaluation of condition indices and predictive models for noninvasive estimates of lipid mass of migrating Common Yellowthroats, Ovenbirds, and Swainson’s Thrushes. Journal of Field Ornithology 79(1):80-86. Request a copy.

Seewagen, C. L. and E. J. Slayton. 2006. Historical accounts of Bicknell’s Thrush in New York City and a new record for Bronx County. Kingbird 56(3):210-219. Download PDF.