Code

CCBTR-00-06

Publication Date

2000

Abstract

The Bachman’s Sparrow (Aimophila aestivalis) is endemic to southeastern North America. Following a dramatic northerly range expansion in the late 1800’s and early 1900’s, this species has been contracting back to the core of its historic range in the extreme southeast. Population declines along the northern fringe of the species range have likely been due to secondary succession within abandoned farmland and the increased use of sod-forming grasses. Declines within the core of the breeding range have been due to degradation and loss of the southeastern pine ecosystem and an effective fire suppression program. The Bachman’s Sparrow is a species of conservation concern throughout its current breeding range. In Virginia, where distribution has declined from 16 counties prior to 1969 to just 4 counties after 1969, the species is listed as threatened. Bachman’s Sparrows were discovered on Fort A. P. Hill in 1993 during a natural history inventory conducted by the Virginia Department of Conservation and Recreation, Division of Natural Heritage. These birds represent the northern-most breeding population throughout the entire species range. The small population evidently persists because frequent fires resulting from artillery impacts have maintained the site in a savanna-like condition. The Bachman’s Sparrow is a disturbance-prone species that occupies a narrow disturbance/successional niche. The species requires pine or open savannas with a high density of grasses and forbs in the first meter layer above the ground and low densities of vegetation in the second to forth meter layer above the ground. For most locations, habitat maintenance depends on a 3-5 year disturbance interval. In the absence of such disturbance, most habitat patches will become unusable within a short period of time as succession proceeds beyond where it is suitable for the species. Management recommendations include 1) an evaluation of the current breeding population, 2) establishment of an annual population monitoring program, and 3) maintaining a fire program that will perpetuate the savanna habitat.

Species

Bachman's Sparrow

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