194 LIFE HISTOEIES OF NOETH AMERICAN BIRDS. 



Even in the more southern parts of their range nitrification rarely begins 

 before April 15. In the southern New England States, as well as in New 

 York, Pennsylvania, Indiana, Michigan, Minnesota, Nebraska, Cooper's Hawk 

 occasionally begins laying about May 1, but usually not before the second 

 week of this month and frequently later. Even in Lower California and 

 southern Arizona it rarely lays as early as April 20, and in the mountain 

 regions of Colorado and Montana the time is protracted until the beginning 

 of June. 



Mr. Denis Gale, of Gold Hill, Boulder County, Colorado, writes me: 

 "On June 25 I found a nest of a Cooper's Hawk containing four unmarked 

 bluish white eggs, resting upon some thin flakes or scales of spruce bark, 

 which alone constituted the lining of the nest, the available contrivance for 

 which was a large bunch of matted scrub, an excrescence upon a horizontal 

 limb, about 18 inches from the trunk and about 20 feet from the ground. 

 This bunch consisted of a wonderful growth of very densely interlaced twigs, 

 the surface of which offered a commodious nesting site, having not only an 

 ample flat area, but a sufficient depression in its center to meet every require- 

 ment for a nest. On July 2 these four eggs were represented by four bright 

 lively Hawklets, densely covered with white down. Neither food nor feathers 

 of any kind were found in or about the nest. The character of this species 

 is bold and brave, especially so in defense of its young. It has a rapid and 

 graceful flight. The skill with which it pursues its devious path along a 

 creek bottom, noiselessly following the intricate opening close to the ground 

 through the trees and undergrowth is remarkable. 



"From the date at which they have their young to provide for, until late in 

 the season, this seems to be their favorite mode of hunting, but especially is it 

 so after the hen Grouse, accompanied by her young brood, has sought such 

 localities for food and water, and where they loiter throughout the summer." 



On the Pacific coast, in Oregon, Washington, and Idaho, I found Cooper's 

 Hawk rather rare, while in southwestern Montana it is more abundant than any 

 of the other Raptores. It is also common in Arizona 



Throughout the greater part of the year Cooper's Hawk is usually a 

 silent bird and rarely utters any notes, but during the mating season it 

 frequently emits a cackling or chattering sort of noise, also a note something 

 like "tick, tick" frequently repeated. When disturbed on the nest, it usually 

 screams shrilly and violently, but generally flies off and watches proceedings 

 from a safe distance. Others, however, show a good deal of courage at times, 

 and boldly dash at the intruder. 



As far as known only a single brood is raised in a season, incubation last- 

 ing about twenty-four days, the male assisting to a slight extent only in these 

 duties, but keeping its mate supplied with food. The number of eggs laid 

 varies from two to six. In the more southern parts of its range it usually 

 lays three or four, and sometimes but two eggs, while along our northern 

 border and the southern New England States, they range from four to six in 

 number, sets of five being rather common, 



