170 



PACIFIC COAST AVIFAUNA 



No. 14 



grass country of this region lies in the l'Pi)er Sonoran. It is common in this 

 zone in migrations, however. 



The migrations take place in ]\Iareh, and in Octo))er or Novemlier. The 

 average date of arrival at Terry is IMarch 25, tlie earliest, March 20, 190.'^; the 

 average at Columbia Falls is IMareli 28, with the eai-liest, JMarch 9, 1895 (Cooke. 

 1907, p. 205). Other dates are: Spring Hill, Gallatin County, ."March 19, 1909, 

 German Gulch, Silver Bow County, March 10, ]910; Helena, INIarch 12, 1911; 

 Luhec, March 28, 1912; Poison, IMarch 10, 1918; Bitterroot Valley, March 4, 

 1910, March 14, 1911, INIarch 11, 1912, and February 26, 1913 (Bailey, MS). 

 Fall migration dates are: Columbia Falls, November 6, 1896 (Cooke, 1907, p. 

 205) ; Cinnabar Basin, Park County, October 25, 1908; Pipestone Creek, Jeffer- 

 son County, October 7, 1909. Fall dates for this species are rare, for the bird 

 seems to become inconspicuous for some reason after early August, ^ly records, 



Fig. 35. Male Mountain Blukbird 

 AT NEST. Pipestone Creek, Jef- 

 ferson County; June 20, 1910. 



kept daily for five years, show that the ^Fountain Blnel)ir(l was seen very sekloni 

 in September and October. 



Nesting begins normally, early in Mny. I found a paii- starting to build a 

 nest in a cabin in Sunday Gulch, Silver Bow County, Ai)ril 5, 1910, but tlic nest 

 was not completed, and in that year the spring was exceptionally cai'ly. At 

 Choteau birds were building nests on xMay 10, 1912, and the first egg was laid 

 May 14. I have seen birds feeding young in Bozeman by May 29, 1911, and th(^ 

 first young are usually on the wing by June 15. Second brood nests begin Ihe 

 hitter i)art of June. I have seen ])irds of one pair nest building June 21, 1910, 

 when another pair were still feeding young of the first brood in the nest near-by. 

 [ have seen young just out of the nest late in July, but 1 l)elieve the nesting is 

 entirely over by early August, as the birds flock in the mountains about that 

 time. They may often be found at high elevations, in the stunted timbci' of the 

 iludsonian zone, with the first cold snap in the first week of August. 



