1913 J Camkkon, Swaimon'a Hawk in Montana. 381 



NOTES ON SWAINSON'S HAWK (BUTEO SWAINSONI) 



IX MONTANA. 



BY E. s. ( AMERON. 



Plates XII and XIII. 



II. Food. 



In his standard work on 'The Hawks and Owls of the United 

 States' I>r. A. K. Fisher, gives a summary of eighteen stomachs 

 of Swainson's Hawk examined by him as follow-,: "Seven con- 

 tained small mammals; eight, insects; three, reptiles; three, 

 batrachians, and three were empty." My own conclusions, from 

 observations made at fourteen nests, are thai Swainson's Buzzard 

 prefers frogs, grasshoppers, and mice, in the order named to any 

 other food when it can get them. Grasshoppers form the staple 

 sustenance of these hawks in .Montana. In common with all 

 birds, however, the hawk's food habits vary with season and local- 

 ity, and in spring, when its favorite prey is unobtainable, -mall 

 birds and cotton-tail rabbits (Lepus artemisice) are attacked, 

 awards the former, Lark Buntings {Calamospiza melanocorys), 

 which were often exceedingly numerous around the nesting site, 

 are, in my experience, the only species ever taken — the color and 

 soaring habits of the males rendering them peculiarly conspicuous. 

 'Cotton-tails,' now very scarce owing to an epidemic amongsl 

 them, were at one time remarkably abundant, and fell frequent 

 victims to buzzards and Great Horned Owls. One of these small 

 hares, weighing under three pounds, which dart for their nearby 

 holes at lightning speed upon the first alarm, was found in the 

 nesl of a Swainson's Hawk, and testified thereby to the venatorial 

 skill of its capturer. In Alaska Mr. Da 1 1 found the hones of rabbits, 

 squirrel-, and ducks in the nest of Swainson's Hawk, 1 but I have 

 never known any prairie dogs, poultry, or game birds, to be taken 

 by it. Con-tant observation was kept upon a pair of Swainson's 

 Hawks which nested in my vicinity in 1908 and L909 by my wife, 



1 North American Birds, Vol. Ill, p. 269. 



