Distribution maps were prepared from data collected in a survey of birds in the
Park during the winter of 1999/2000. Ten-minute counts of birds heard or seen
were conducted during January or February at points spaced at 250-m intervals.
This survey is part of a Bird Inventory project for parks in Washington, D.C.,
and in suburban Maryland that are administered by National Capital Parks-East.
The project, conducted by biologists from the USGS Patuxent Wildlife Research
Center, is jointly funded by the Inventory and Monitoring Program of the
National Park Service and by the U.S. Geological Survey.