556 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



From the Eed River and correspondiog longitude, west to tbe Eocky 

 Mountains, it breeds in profusion, and during the greater part of the 

 year it is, without exception, the most abundant, universally diffused, 

 and characteristic species of the prairie avifauna. Numerous specimens 

 were taken, not only along the parallel of 49°, but also on the Missouri 

 and Milk Elvers, and the species accompanied our line of march into 

 the mountains. The individuals bred in this dry and sterile region are 

 usually lighter-colored than those of better- watered areas, and are those 

 which I have designated by the term leucolcema, in indication of a slight 

 geographical differentiation. 



The Horned Lark is one of the few species which, in this latitude, usu- 

 ally rear at least two broods each season, — a fact which in part accounts 

 for the preponderance of individuals over those of the species with which 

 they are associated. I have already adverted to the extremely early 

 nesting-time which has been ascertained, and have only to add that the 

 period of reproduction is protracted through July. I have observed 

 young birds on the wing in June, and found fresh eggs in the nest dur- 

 ing the latter half of July. In fact, all through the summer months 

 the troops of Larks everywhere to be seen consist of old birds mixed 

 with the young in all stages of growth. The great flocks, however, are 

 not usually made up until the end of the summer, when all the young 

 are full-grown, and the parents, having concluded the business of rear- 

 ing their young, have changed their plumage. The young of the first 

 brood soon lose the peculiar speckled plumage with which they are at 

 first covered; the later ones change about the time the feathers of the 

 old birds are being renewed. The agreeable warbling song is scarcely 

 to be heard after June. 



While it is not probable that any of these birds endure the full rigors 

 of winter in the exposed country of this latitude, I am unable to say 

 when they retreat. They continue abundant until October, and prob- 

 ably only retreat before the severe storms of the following month, to 

 return again in March, if not in February. It is brave and hardy, one 

 of the few birds that weather the terrible storms that usually prevail in 

 April in the Missouri region. 



The nest of the Horned Lark may be stumbled upon anywhere on the 

 open prairie. It is a slight affair, — merely a shallow depression in the 

 ground, lined with a few dried grass-stems. The eggs are four or five in 

 number, measuring nearly an inch in length by about three-fifths in 

 breadth; they are very variable in contour. The color is well adapted 

 to concealment in the gray-brown nest, being nearly the color of the with- 

 ered materials upon which they rest, thickly and uniformly dotted with 

 light brown. The eggs and young birds, like those of other small spe- 

 cies nesting on the ground in this region, often become the prey of the 

 foxes, badgers, and weasels, if not also of the gophers. 



The Horned Lark is a sociable bird, not only highly gregarious with 

 its own kind, but one that mixes indiscriminately with several other spe* 



