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1921 BIRDS OF MONTANA 61 



state. Records in the eastern part of the state are few. There are no records of 

 this species by the earlier observers, which leads to the belief that the species has 

 become common in recent years. Winters occasionally on the west side of the 

 divide. Records in the eastern half of the state : Custer and Dawson counties, 

 summer resident, probably breeds (Cameron, 1907, p. 260) ; Fergus County, nest 

 and four eggs, June 6, 1900 (Silloway, 190;3a, pp. 27-28, and 1901c, pp. 70-71) ; 

 nest at Flathead Lake, July 3, 1900, four eggs advanced in incubation (Sillo- 

 way, 1901a, p. 31). Young are nearly full grown and ready to leave the nest 

 by about August 25 in Powell and Deer Lodge counties. This bird nests most 

 commonly in the mountains in low thick growths of spruce. In the prairie 

 region they probably nest in cotton wood groves, but the nest has yet to be found 

 there. 



Migration dates: Spring. May 13, 1909, Big Creek, Park County; April 

 12, 1910, Divide Creek, Silver Bow County; April 23, 1911, Anaconda; May 8, 

 1912, Choteau. Fall. October 6, 1908, Gallatin County; September 26, 1910, 

 Race Track; September 18, 1911, and September 13, 1912, Choteau. 



Winter records: Silver Bow, January 2, 1911 (Saunders, 1912a, p. 25); 

 Bitterroot Valley, usually rare in winter, but common at that season when Red- 

 polls are abundant (Bailey, MS). 



109. Accipiter cooperi (Bonaparte) 



Cooper Hawk 



Summer resident throughout the state but commoner in the western half in 

 the mountains. Less common than A. velox. There are no nesting records from 

 extreme eastern JVIontana, where it may be only a migrant, though there are sev- 

 eral records in late summer. There are no definite nesting records from any 

 section ; so far as records show the nest has never been found in the state. In 

 most places the hawk is regarded as rare, but Bendire calls it the commonest 

 hawk in southwestern Montana (1892, p. 194). 



Migration dates: Dawson County, April 30, 1903 (Cameron, 1907, p. 260) ; 

 Silver Bow County, April 30, 1910 ; Anaconda, April 20, 1911 ; Choteau, April 

 22, 1912. Fall: Custer County, September 13, 1893 (Cameron, 1. c). 



110. Astur atricapillus atricapillus (Wilson) 



Eastern GoshaW'K 



A fall migrant through the eastern half of the state, extending its range 

 west into the mountains east of the continental divide, and perhaps farther west- 

 ward. This form may be a summer resident in some parts of the state, but the 

 only definite identification of a breeding bird proved to be that of the western 

 subspecies. Records: Custer and Dawson counties, September 22, 1903, October 

 18, 1905, November 19, 1905, September-October, 1906, October 18-27, 1906 

 (Cameron, 1907, pp. 261-262). Gallatin County, three seen and one taken 

 (Richmond and Knowlton, 1895, p. 302). Gallatin River, October 30, 1908 

 (Saunders, 1911a, p. 36). Park County, October 21-25, 1908. 



Winter record: Gallatin County, December 21, 1908 (Saunders, '1909a, 

 p. 35). 



