A population study and management suggestions for the Denslow's Sparrow (Ammodramus henslowii) at Fort, Drum, NY

Abstract

The Henslow' s Sparrow (Ammodramus henslowii) is one of the most threatened grassland bird species in North America. It is listed as endangered, threatened, or a species of concern in 30 of 32 states and one Canadian province in its historic range. This obligate grassland breeding bird species is now clustered in smaller areas within New York State, and with fewer numbers than before. The largest concentrations currently occur in Jefferson County, NY, within the St. Lawrence Plain ecozone, particularly at the Ft. Drum military installation. The declining populations in the Northeast are likely due to breeding and wintering habitat loss, primarily resulting from changing agricultural practices and land use over time. Henslow' s Sparrow breeding behaviors and narrow habitat preferences make it a challenging species to manage for without hindering habitat for other grassland breeding birds. Specific management suggestions for Fort Drum are recommended, including seasonal timing, mowing instructions on height and needed area, and a 3-4 year rotational mowing scheme. The challenges of developing an environmental management plan for an active military training installation, including interdepartmental cooperation and flexibility within a multi-use land area, are also discussed.