HENSLOW'S SPARROW HABITAT ASSOCIATIONS ON KANSAS TALLGRASS PRAIRIE

Abstract

We examined macro- and microhabitat characteristics of breeding Henslow's Sparrows (Ammodramus henslowii) on Fort Riley Military Reservation, Kansas during 1995 and 1996. Survey points were identified at the macrohabitat scale as either grassland, savanna, or woodland edge. A military disturbance index was used to quantify the severity of training disturbance to the vegetation at survey and bird use sites. At the large scale, Henslow's Sparrows were associated with grassland habitat last burned in 1993, two or three years previously. Microhabitat at Henslow's Sparrow use sites had lower tree density than random survey points, but neither shrub density nor military disturbance index differed between use sites and survey points during spring. In summer, the military track index was higher on Henslow's Sparrow's use sites. Habitat used by Henslow's Sparrows was consistently tall and dense vegetation with high litter cover during early spring, late spring, and summer whereas the vegetation of random survey points changed in response to vegetation growth. Characteristics of Henslow's Sparrow use sites included high cover by litter and dense, structurally homogeneous vegetation, whereas litter depth and standing dead vegetation, physiognomic diversity, and military disturbance did not differ from random survey points.