\ 



1921 BIRDS OF MONTANA 139 



containing young was found under a bridge at Dutton, July I'A, 1916 (DuBois, 



MS). 



262. Iridoprocne bicolor (Vieillot) 



Tree Swallow 



A summer resident throughout the state. Very common in the northwester)! 

 part of the state, rare or locally common in most places elsewhere. Breeds in 

 the Transition zone in holes in trees, or in bird-houses, crevices in buildings, and 

 similar places. Shows a marked preference for the vicinity of water. While 

 this species breeds locally in many parts of the state, at Flathead Lake it is th»- 

 most abundant swallow, breeding in dead trees all around the lake shore, and in 

 bird-houses in towns and settlements. It is also common at Kalispell and on the 

 Flathead Reservation, and is reported as a connnon breeder in the Bitterroot 

 Valley (Bailey, MS). In the mountainous half of the state, east of the conti- 

 nental divide, this species has been reported only from Gallatin County (Rich- 

 mond and Knowlton, 1894, p. 306), and from Park County and the vicinity oi* 

 Helena. In the prairie region it is reported from Fergus County (Silloway, 

 1903a, p. 60), Chister and Dawson counties (Cameron, 1908a, p. -to), ^lusselsheil 

 River (Allen, 1874, p. 53). and Great Falls (Williams, 1888a. p. 16). 



The migrations are irregular, the species arriving most cojnmonly in April 

 and leaving in the latter part of August. Four years' observations at Great 

 Falls give April 29 for the average, and April 28, 1891, the earliest, while it- 

 was noted at Missoula, March 26, 1916 (Oberholser, 1917, p. 324). Other dates 

 of arrival are: Bozeman, ^lay 4, 1909; Helena, April 9. 1911. In fall the last 

 birds are usually seen late in August. Dates are as follows : ^lissoula, August 

 8, 1915 (Oberholser, 1917, p. 325) ; Eight Mile Creek, Park County, August 24, 

 1908; Logan, Gallatin County, August 25, 1909. 



Nesting probably begins in late June. A nest with one egg was found a1 

 Flathead Lake, June 24, 1900 (Silloway, 1901a, p. 22). I have noted birds feed- 

 ing young at Flathead Lake in July, and have seen young on the wing at Poison, 

 July 27, 1915. The birds have been noted feeding young in Gallatin County in 

 August (Richmond and Knowlton, 1894, p. 306). 



263. Tachycineta thalassina lepida Mearns 



Northern Violet-green Swallow 



A summer resident evidently throughout the state, rare or local in the east 

 ern half, but very common in the proper localities throughout the western half. 

 Breeds in the Transition zone, in holes in rocks along the sides of river canyons, 

 and less commonly in bird houses or holes in trees. Reported by nearly all ob- 

 servers in the western half of the state, but only by a few in the eastern half. 

 The eastern records are as follows : ]\Iouth of Tongue River and along the Yel 

 lowstone above it (Allen, 1874, p. 53) ; abundant on the Big Horn River (Mearns 

 1904, p. 21) ; Powder River (Cameron, 1908a, p. 45) ; west of Billings (Thomas. 

 MS). 



The migrations take place chiefly in May and August. It is stated to ai'rivi' 



