1921 BIRDS OF MONTANA 91 



City, March 30, 1901, by Hedges (coll. Univ. Montana). I am certain that I 

 have seen many birds of this race just over the Montana border in Harding 

 County, South Dakota, and I believe that more extensive collecting in eastern 

 Montana will show it to be not uncommon in hard winters. 



In western ^Montana it is recorded from the Bitterroot Valley, Chief ]\Ioui)- 

 tain Lake, and the Sun River (Dwight, 1890, p. 143) ; from the Gallatin Valley 

 (Richmond and Knowlton, 1894. p. 304; Saunders, 1911a, p. 39); from Deer 

 Lodge and Jefferson counties (Saunders, 1912a, p. 27) ; from Teton County 

 (Saunders, 1914a, p. 135) ; and from the Bitterroot Valley (Bailey. MS). 1 have 

 also seen this form near Helena, and taken it near Livingstone, in Park County. 



This subspecies evidently leaves in March, and arrives probably in Decem- 

 ber. Dates are : Livingstone, December 9, 1908 ; Helena, ]\Iarch 26, 1911 ; and 

 \ Choteau, March 10, 1912. 



182. Otocoris alpestris leucolaema (Coues) 



Desert Horned Lark 



An abundant summer resident throughout all of the state except the north- 

 western portion, where it is probably replaced by merriUi. All observers men- 

 tion the occurrence of this species and most of them regard it as abundant. In 

 tbe prairie region it is one of the commonest birds, breeding on the dry, short 

 grass areas, such as occur on the higher benches. In such situations this bird is 

 one of the very few species to be found. In the valleys of the mountainous half 

 of the state, it is a little less common, mainly because the dry short grass areas 

 it prefers are less common. 



The migrations take place very early in the spring, in fact the Desert Horned 

 Lark is the first common song bird to arrive, preceding the Robin and Mountain 

 Bluebird by a week or more. Although a few individuals winter, it is easy to 

 determine the beginning of the spring migration, because the birds always mi- 

 grate in flocks, and are suddenly common the first day of their arrival. Dates of 

 spring arrival are as follows : Gallatin County. ^larch 9, 1909 ; Silver Bow 

 County, March 3, 1910; Helena, :March 12. 1911; Choteau, March 10, 1912, 

 March 3, 1913. Fall migration is less easily determined, as it is difficult to sep- 

 arate late fall migrants from wintering birds. I believe that in Avestern Montana 

 at least fall migration does not entirely cease till nearly the first of January, as 

 my observations have showTi that this form of Horned Lark is more abundant late 

 in December than in the other two winter months. I have no definite dates 

 however. The majority of the summer birds are gone by the last of November. 



]\Iost writers are silent about the winter occurrence of this bird. In eastern 

 Montana it is undoubtedly commoner in winter than arcticola. In western Mon- 

 tana I do not think this the case. Too little winter collecting has been done to 

 determine this with certainty, but the two forms are not difficult to determine in 

 the field, when observed closely in a good light, for the throat of leucolaema is 

 most intensely yellow at this season, while that of ar<'ticola is white, and since 

 the birds flock together, the difference in size is usually apparent. My observa- 

 tions go to show that after the first of January flocks of horned larks are mainly 

 arcticola with only an occasional specimen of Iciicolaciiia. 



