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National Capital Parks-East (NACE) is a diverse set of parks, totaling over 3200 hectares, within Washington, D.C., and in suburban Prince George's and Charles counties, Maryland. The parks include urban squares, recreation areas, parkways, historical sites, and natural areas. Bird populations in these parks were surveyed during April 1999 through December 2000 by biologists from the USGS Patuxent Wildlife Research Center, Laurel, Maryland. The project, jointly funded by the Inventory and Monitoring Program of the National Park Service and by the U.S. Geological Survey, was aimed at documenting the spatial distribution and relative abundance of birds, providing data that will facilitate decisions on future use and management of the parks. The information should also increase public awareness and appreciation of the parks and their biotic resources.

Survey Design and Field Methods

A grid of points spaced at 250-m intervals was generated in ARC/INFO, and overlaid on a Geographic Information System coverage of NACE property boundaries. Points within park boundaries were located in the field with a Global Positioning System receiver. A few additional points were located so that all sites would be sampled.

The basic survey technique was 10-minute counts of birds heard or seen at the points. Counts were conducted at 453 points during the 1999 nesting season, and at 448 points during January-February 2000. During the spring and fall, the survey was designed to compare migrant bird species richness among parks or habitat types; sampled points (spring 1999, 281 points; fall 1999, 333 points; spring 2000, 253 points) were randomly selected with replacement, so not all points were sampled but some were sampled more than once. The protocol was modified for counts during fall migration, when birds rarely vocalize and some species are in drab plumage: a taped recording of chickadee calls and human "spishing" was broadcast at points to lure birds closer to the observer, facilitating visual identification and increasing species' detection probabilities. Count length was reduced to 5 minutes in spring 2000 so more points could be sampled in a morning.

In addition, special surveys were conducted in some parks for nocturnal birds, and to document waterbird or shorebird use of wetlands or waterways in or adjacent to the parks. Occasional visits were also made to parks throughout the project to document seasonal occurrences of bird species not detected on the point count or special surveys.


This page created on 12/11/2000 by Deanna K. Dawson and Gregory A. Gough. Last updated 12/11/2000