PEAIBIE FALCON. 105 



At present tlie data we have on the food of this Hawk is not enough 

 to decide whether the species should be protected or persecuted. 



The following species of mammals and birds were positively identi- 

 fied among the stomach contents: 



MAMMALS. ' BIRDS. 



Spei'mophilus tridecemlineatus pallidua. Lopliodytes cucullains. 



SpermopMlus richardsoni. CalUpepla gambeli. 



Tympanuclius americanus. 



Zenaidura macronra, 



Otocoris alpeatris arenicola. 



Marporhynohus crissalis. 



The nest is placed usually on a shelf or in a niche on the perpen- 

 dicular surface of a 'cut bank,' so common in parts of the West, or 

 among the crevices of rocky cliffs. It is probable that this Falcon also 

 builds in hollows of trees, as the Duck Hawk sometimes does. The 

 eggs, which are usually three in number, though sets of four occasion- 

 ally have been found, are deposited early in May, and by the latter 

 part of July the young are able to leave the nest. 



The Prairie Falcon, as the name imphes, is a typical plains bird and 

 inhabits the dryinterior. In this respect it differs from the Duck Hawk, 

 for the latter bird is not commonly met with away from tide water or 

 the vicinity of the larger lakes, while the former is just as rare in such 

 localities, the exception being in autumn when it is attracted to the 

 sloughs and lake marshes by the abundance of food, at which time the 

 two species associate. 



The flight of this Hawk is swift and graceful, though in most cases it 

 is carried on at no great distance from the ground. Itis not a shy bird 

 except in sections where it has been persecuted and has learned that 

 man is its worst enemy. 



DESCEIPTIOKT. 



Lower leg feathered for not more than upper half, posterior side al- 

 most wholly naked. Top of head grayish brown, streaked with dusky. 

 Above, pale grayish brown indistinctly but broadly barred with pale 

 clay color or bluish gray. Below, white, the flanks heavily spotted or 

 blotched with dusky. 



Length : 17 to 20 inches (431 to 509"""); extent, 40 to 43 inches (1015 

 to 1092"'">); wing, 11.60 to 14.30 inches (294 to 363'"">)j tail, 6.40 to 9 

 inches (162 to 228'""^). 



