1921 BIRDS OF MONTANA 1,59 



containing young- was found uiuici' a luidgc at Dutton, July i:i, IDKi ( l)uP>ois. 

 MS).. 



262. Iridoprocne bicolor (Vipillot! 



Tree Swaleow 



A siunnier rcsidcut throughout tlic stat(\ N'cry common in the iioi1h\i'cst('rii 

 |iai-t of the state, rai-i' or locally common in most places elsewhere. Hi'eecls ii, 

 the Transition zone in holes in trees, or in bird-houses, crevices in i)uildinus. and 

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

 this species breeds locally in many parts of the state, ;it Flatheail Lalcc it is tin 

 most abundant swallow, lireeding in dead trees all around tlie lake shore, and in 

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

 i'^lathead Reservation, and is reported as a common l)reeder in the Bitterroot 

 Vallt\v ( P>ailcy, ilSl. In the mountainous half of the state, east of the conti- 

 nental divide, this species has l)een I'eported only from Gallatin County (Rich- 

 mond and Knowlton, lSr)4. p. 'Mn>). and fi-om Park County and the vicinity of 

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

 1903a. p. ti(M, Custer and Dawson counties (Cameron, 1908a, p. 4.'il, Musselshell 

 River (Allen, lS7-t, p. 5:Vi, and Great Falls (Williams, ISSSa. p. Kii. 



The migrations are irregulai', the species ai-riving most commonly in Ain-il 

 and leaving in the lattei- part of August. Four years' observations at Greal 

 Falls give April 29 for the avei'age, and April 2S, 1S91, the earliest, while it 

 was noted at Missoula, March L!(i, 191(i (Oberholser, 1917, p. 324). Other tiatcs 

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

 iiirds are nsually seen late in Augnst. Dates are as follows: ^lissoula. August 

 8, 1915 (Oberholser, 1917, ].. 82.5) ; Eight :\Iile Creek. Park County. August 24, 

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



Nesting proi)ably begins in late June. A nest with one egg w'as found at 

 Flathead Lake, June 24, 1900 (Silloway, 19()la, p. 22). I have noted birds feed- 

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

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

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



263. Tachycineta thalassina lepida M earns 



NoHTiiERX Vior.ET-cniEEX Swallow 



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

 ern half, but very common in tin' iiro])ei' loc;ditics throughout the western half. 

 Breeds in the Ti'ansition zone, in holes in i-oeks along the sides of river canyons, 

 and less commonly in liird houses or holes in trees. Rejiorted by nearly all oh- 

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

 The eastern records arc as follows: Mouth of Tongne River and along the Vel 

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

 1904, p. 21) : Powdei' River CCameron, 19(lS;i. p. 45) ; west of Billings (Thomas. 

 MS), 



Till' uiigrations tai^( place I'hiefly in .M.iy and .\ugust. it is stated to ari'i\'e 



