U.S. Geological Survey Home Page USGS Patuxent Wildlife Research Center Science Meetings; dedicated to Chandler S. Robbins USGS Patuxent Wildlife Research Center; Science Meetings dedicated to Chandler S. Robbins Dedicated to Chan Robbins USGS Patuxent Wildlife Research Center; Science Meetings dedicated to Chandler S. Robbins Poster Abstracts from USGS Patuxent Wildlife Research Science Meetings, October, 2006
Patuxent Science Meeting 2006 Poster Abstract

60-year changes in Patuxent breeding birds

Robbins CS

Three methods, Point Counts, Breeding Bird Survey, and Atlas, are used to detect bird

population changes on and adjacent to the Patuxent Research Refuge. The initial count of

5,429 pairs of birds of 80 species nesting on Patuxent's original 2,656 acres was conducted in

1943. Subsequent field projects have documented habitat preferences and changes in species

composition and abundance, the most recent being point count surveys by Danny Bystrak in

1996 and 1997 and the MD/DC atlas projects of 1983-87 and 2002-06. Of the 80 original

species, three grassland birds are now extirpated: Horned Lark, Vesper Sparrow, and Henslow's

Sparrow. Of the 46 additional breeding species found here since the original survey in 1943, 13

had responded to the construction of wetlands, five were introduced by man, two were attracted

by nest boxes, one responded to aging of the deciduous forest, five were southern species

expanding northward, six were species at the edge of their breeding range, eleven were species

for which little suitable habitat was available, and three remain unassigned. Atlas data are used

to show bird population changes at Patuxent over the past 20 years. Atlas studies can be

extremely valuable as conservation tools. Most of the eastern United States has already been

covered by one or two atlas studies. Everyone lives in an atlas block, so the changes detected

relate to everybody's back yard or local park or favorite birding area.

Friday, September 22, 2006



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