Swainson Hawks Working on Grasshoppers Again
Swainson Hawks Working on Grasshoppers Again.-About 30 miles southeast of Sonora, Sutton County, Texas, on May 3 and 4, 1945, considerable numbers of Swainson Hawks (Buteo swainsok) were observed feeding on the numerous grasshoppers on the overgrazed ranges. The hawks were usually observed flying low or perched on the ground. Twenty-five or more were observed at different times along a five-mile stretch of ranch road.
The grasshoppers, and likewise the hawks, seem to be more numerous on the overgrazed ranges infested with bitterweed. We saw none of the hawks and few grasshoppers on the better grassed pastures.
The observed relationship between the Swainson Hawk and the grasshopper outbreak was undoubtedly significant; also, although no actual grasshopper counts were made, it was obvious that a relation existed between the grasshopper plague and an extreme overgrazed condition of the range, as pointed out years ago by Treherne and Buckell (Grasshoppers of British Columbia, Dominion Canada Dept. Agr., Bull. 39, n.s., 1924).-WALTER P. TAYLOR, Texas Cooperative Wildlife Research Unit, College Station, Texas, September 22, 1945.
