A grassland species, Henslow’s sparrow historically bred in the tallgrass prairies of the Great Plains. It now nests mostly in neglected grassy fields, pastures and meadows. There are two distinct subspecies of the sparrow: eastern and western. The western sparrow inhabits the rough parallelogram described by eastern South Dakota, southern Ontario, central Kansas and central West Virginia. The eastern variety can be found along the American east coast from northern New York to central North Carolina. A possible third subspecies once resided in coastal Texas, but is considered extinct.
A shy bird, the Henslow’s sparrow will usually flee interlopers on foot, rather than flying away. However it is social within its species, breeding in loose colonies, building nests at the base of grass clumps and feeding on insects and seeds. The sparrow requires very specific breeding habitat: dense grass with standing dead vegetation and little to no woody vegetation.
It is the loss of this habitat that has primarily contributed to the species’ decline. Changes in agricultural practice, especially in the Midwest, have converted fields once used for grazing and hay to specialized crop fields unsuitable for the sparrow. Consequently, it has been on the National Audubon Blue List since 1974 and is listed as Endangered or Threatened in 12 states.
February 25, 2011