Henslow's Sparrow (Ammodramus
The Henslow's Sparrow (Ammodramus henslowii) has been identified as a focal species due to a decline in its range-wide breeding population estimated at an average annual rate of -7.5% since the mid-1960s. A small, inconspicuous grassland bird, this sparrow has suffered primarily from the drainage and degradation of natural grasslands, habitat loss to suburban development, and the conversion of hay fields and pastures to cultivated crops.
Other factors impacting this species include suppression of natural fire regimes needed to maintain grasslands and the frequent mowing of grasslands for hay production that greatly reduces breeding success. Its winter range and ecology remain poorly known, although one recent study suggests these sparrows may have very specific habitat requirements during winter that could also be a factor regulating population size.
Herkert, James R., Peter D. Vickery, and Donald E. Kroodsma. 2002. Henslow's Sparrow (Ammodramus henslowii). In: The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology. Retrieved from http://bna.birds.cornell.edu/bna/species/672.
Plentovich, S., N. R. Holler and G. E. Hill. 1999. Habitat requirements of Henslow's Sparrows wintering in silvacultural lands of the gulf coastal plain. Auk 116: 109-115.