PRAIRIE FALCON 23 



The female docs the brooding, although the male will sometimes take 

 her place under unusual conditions. Usually the male, unless hunting, 

 will perch on a tree somewhere near the nest. Decker and Bowles 

 (1930) say that for some reason she will remain with the eggs when in 

 an open nest almost to the last extremity, "while in one of the pot hole 

 nests she may flush at some little distance." They continue: 



The period of incubation does not seem to influence her actions in this respect to 

 any great extent so far as we have seen. We had one most fascinating exhibition of 

 a close sitting bird at one site where an old nest of the Raven was used. One of us 

 was walking along the top of the cliff, while the other walked along at the base, 

 the man at the top being considerably further in advance. Presently a nest was 

 sighted at very close range with the bird crouched upon it and most intently 

 watching the man below her. The man at the top made very little noise and she 

 had not seen him, so he had a perfect opportunity to study her. She flattened 

 herself down into the nest so far as to be completely out of sight from any direction 

 excepting directly above and remained in that position until the man below was 

 almost up to her. Then she stood up in the nest and commenced her battle cry 

 that gives such a never failing thrill to the bird lover, not leaving until she knew 

 it was useless to remain any longer. 



In its action around the nest we have never known a Falcon to actually strike 

 a human being. 



Between the "close sitters" and the wary birds there are all grada- 

 tions. After the female has been driven from her nest, she will seldom 

 return to her eggs while the enemy remains in sight. Should the 

 intruder suspend activities and remain quiet, she may perch more 

 or less nervously on a tree not too far away; but renewed movement 

 will often bring her back to scream and swoop. She is evidently the 

 more aggressive and the more concerned over the eggs. The male 

 usually contents himself with circling high overhead. 



Throughout most of its range this falcon is a valley or foothill bird, 

 so that it comes as a surprise to hear of its hunting, and even breeding, 

 far above timberline. Merriam (1890) says: "A pair of these Falcons 

 had their nest on a high cliff in the crater of the main peak of San 

 Francisco Mountain, and another pair had possession of a similar 

 ledge on Kendrick Peak." Both of these locations were at least 1 1 ,000 

 feet above sea level. Bergtold (1928) says that in Colorado the prairie 

 falcon "breeds up to 10,000 feet." Lowe (1895) says that "one was 

 shot at 10,000" in the Wet Mountains, Huerfano County, Colo. 

 Dr. E. A. Mearns (1890) saw one on June 4, 1887, at the very tip of 

 Humphreys Peak, Ariz., at 12,562 feet, and writes: "These only 

 braved the wind and cold at the summit. The name of 'Prairie' 

 Falcon scarce accords with my recollection of that scene." 



Eggs. — Usually there are four or five eggs to a set in California, 

 Oregon, and Washington. Records of just 100 sets collected in these 

 States show 7 percent contained three eggs, 21 percent four eggs, 70 

 percent five eggs, and 2 percent six eggs. But four sets obtained 

 farther east in Wyoming and Colorado showed one set of two eggs, 



