ABUNDANCE OF BAIRD SPARROWS, AMMODRAMUS-BAIRDII, IN NATIVE PRAIRIE AND INTRODUCED VEGETATION

Endemic grassland songbirds, including the Baird's sparrow (Ammodramus bairdii), are adapted to breed in North American native prairie, an e xtremely rare habitat that is often grazed by cattle and continues to be threatened by cultivation. We determined the degree to which Baird' s sparrow numbers in mixed-grass prairie are associated with plant spe cies composition and grazing pressure. Bird numbers in grazed native p rairie correlated positively with grass/sedge cover and negatively wit h bare ground cover. Mean numbers of singing males were generally high est on ungrazed native prairie and similar in grazed introduced and gr azed native vegetation, suggesting that birds are more affected by gra zing pressure than by plant species composition. What attracts this sp ecies to introduced vegetation remains unclear.