1921 BIRDS OF MONTANA 119 



227. Ammodramus savannarum bimaculatus Swainson 



Western Grasshopper Sparrow 



A summer resident of prairies and of the lower mountain valleys throughout 

 the state. Rare in most places. ^lost common on the prairies to the eastward, 

 and recorded from only two localities within the mountains. In eastern ^lontana 

 it is reported as common on the Yellowstone and Musselshell (Allen, 1874, p. 57), 

 common on the Upper IMissouri (Grinnell, 1876, p. 645), and common in Fergus 

 County (Silloway, 1903a, p. 55). It is reported also from Dawson County 

 (Cameron, 1908a, p. 39). In the western part of the state it is reported from 

 Gallatin County (Richmond and Knowlton, 1894, p. 305, and Saunders, 1911a, 

 p. 42), and from Flathead Lake (Silloway, 1901a, p. 62), the last being the only 

 locality west of the continental divide. 



There are few data on the migration of this species. In Fergus County it 

 arrives about May 10 (Silloway, 1903a, p. 55). It is reported to arrive at Great 

 Falls, May 8, 1885, and May 9, 1887 (Williams, 1888a, p. 15), and the only fall 

 date is Dawson County, September 16, 1904 (Cameron, 1908a, p. 39). 



The only breeding record is of a nest found at Poison, July 27, 1915, con- 

 taining four eggs with incubation advanced (Saunders, 1916c, p. .86). 



\ 



228. Chondestes grammacus strigutus Swainson 



Western Lark ' Sparrow 



An abundant summer resident of eastern JMontana, becoming rare west- 

 ward. Found chiefly in the prairie region, but Avith one or two records in the 

 mountains, and one west of the continental divide. This species is evidently one 

 of the few in the state that are characteristic of the Upper Sonoran zone. In 

 Custer and Dawson counties it is very abundant, nesting in the pine hills, in the 

 badlands, and on the prairies (Cameron, 1908a, p. 39). It is also reported as 

 abundant on the Yellowstone and Musselshell (Allen, 1874, p. 58), on the Upper 

 Missouri (Grinnell, 1876, p. 646), in the Big Horn region (McChesney, 1879, p. 

 2387), at Fort Custer (Mearns, 1904, p. 21), and at Fort Benton (Cooper, 1869a, 

 p. 77). West of these localities the species becomes rare, not having been noted 

 at Lewistown (Silloway, 1903a, p. 55), nor commonly by other observers at 

 points farther west. It is reported from Billings (Jones and Dawson, 1900, p. 

 32) and from Gallatin County (Richmond and Knowlton, 1894, p. 306; Saunders, 

 1911a, p. 42). It is rare in Teton County. Seen once near Choteau, July 18, 

 1911 (Saunders, 1914a, p. 138), and on two occasions at Dutton. one June 24, 

 1915, and three June 4, 1916 (DuBois, MS). The only records w^est of the di- 

 vide are from Missoula, wdiere single birds w^ere seen May 27 and June 28, 1917 

 (Kittredge, MS). 



The migrations take place in late April or early May. Six years' observa- 

 tions at Terry give an average date of arrival as May .7, with April 27 (1897) 

 the earliest. Three years at Great Falls average May 12, with May 8 (1899) the 

 earliest (Cooke, 1911, p. 85). No information regarding the fall migration is 

 available. 



