-470 Cameron, Changes of Plumage in Bxiteo swainsoni. [oct 



xnight easily have missed them for he writes: "I took no specimens 

 in the melanistic state of phimage in which the bird has been de- 

 scribed as another supposed species {B. insignatus); and only saw 

 one in which the entire underparts looked as dark, when the bird 

 "was sailing over me, as the pectoral band of the adult female is." ^ 

 These melanistic birds are by no means uncommon. In the great 

 irruption of April, 1890, I saw numbers of them. The above 

 mentioned writer also states {pp. cii.): "In both sexes, and at 

 all ages the eye is brown, but of varying shade. I have seen no 

 approach to a yellow iris." This is true of all the brown males, 

 but the bluish ash specimens, to which I refer, have brownish 

 yellow irides, with orange legs, feet and cere. The females and 

 immature birds on the other hand, have pale hazel irides, the legs, 

 feet, and cere being chrome yellow. The eyes are blue gray in 

 the newly fledged young, which color probably changes before the 

 ■end of the year. 



Among the twelve examples shot in April, 1890, out of one flock 

 ■eleven were females and immature birds while the 12th, of the 

 lavender type, appeared to be an adult male. As previously stated 

 six of the skins were sent to Dr. P. L. Sclater who wrote (referring 

 to himself and Dr. R. Bowdler Sharpe): "We have come to the 

 conclusion that they are all correctly determined." 



Since learning more about these birds, I regret not having ob- 

 tained and forwarded to him a large series with a view to clearing 

 up the difficulties connected Avith their mutability of plumage. 

 Subsequently to April, 1890, when the immense buzzard host was 

 ■observed, I have met with other small migrations. It does not 

 surprise me that only a small percentage of cinereous males are 

 seen, as in all large bird flocks of different sexes and ages the im- 

 mature young greatly predominate. Nevertheless, out of the four- 

 teen exam])les shot by me two were cinereous birds, which gives a 

 proportion of fourteen percent, without taking the females into 

 •consideration. If Swainson's Hawk employs similar methods of 

 nest building, and meets with similar persecution elsewhere as in 

 Montana, it is no wonder that few birds reach maturity. I have 

 never known these hawks to take jioultry of any kind although 

 they are frequently about ranches. This forbearance, however, 



1 Birds of the Northwest, 1874, p. 357. 



