1584 U.S. NATIONAL MUSEUM BULLETIN 2 37 part 3 



raising themselves up and fluttering their wings. By the ninth day, fear instinct 

 was evident. Before this they had not been much disturbed at the weighing 

 process but now they either crouched on the scale with neck drawn down between 

 the scapulars, or fluttered about trying to escape, cheeping constantly. At this 

 the adults became quite alarmed and circled low over the box containing the 

 scales, uttering sharp alarm notes. 



Regarding the progressive increase in the growth of feathers, 

 DuBois (1937b) has this to say: 



The newly hatched young, as soon as dry, are protected above by fluffy natal 

 down, about one-fourth inch long, of a whitish buff or pale dead — grass color 

 similar to that of young Desert Horned Larks. The invisibility afforded by this 

 covering is truly marvelous. The skin is light-colored but reddish. The tongue 

 and inside of the mouth are of a strong pink color, without spots or marks of any 

 kind. This distinguishes them from young of Desert Horned Larks. 



When the nestlings are four days old, the feathers of their underparts become 

 well sprouted, forming a longitudinal band along each side. When six days old, 

 the natal down of the upper parts has been pushed out on the feather tips so that 

 the covering is a combination of down and feathers. The young are well feathered 

 at the age of eight or nine days. 



Mickey adds: 



By the sixth day, the feather tips had broken from all sheaths except those on 

 the capital tract. Another day was needed for the head feathers to emerge, 

 otherwise, on the seventh day the bird appeared well feathered. Down still 

 clung to the head and occasionally to some of the back feathers on the eighth 

 day. * * * 



The wing feathers developed at a slightly different rate from those on the body 

 proper. The developing flight feathers, enclosed in their sheaths, appeared on 

 the wings on the second day. These sheaths grew from one-sixteenth of an inch 

 on the third day to one-fourth of an inch by the fifth day. On the sixth day, 

 feather tips had broken from the sheaths of the primary coverts and on the 

 inner margins of the secondaries. * * * By the time the bird was ready to 

 leave the nest, the feathers of the secondaries protruded one-half an inch beyond 

 the end of the sheaths and those of the primaries one-fourth of an inch. The 

 primary feathers of a bird captured when eighteen days old measured two inches 

 in length. 



The caudal feathers were the slowest of all to grow. The nestlings were six 

 days old before the tail feathers could be measured. * * * The tail of an eighteen- 

 day-old bird measured one inch in length. At this time the characteristic color 

 pattern of the tail was clearly indicated. 



Early dates for the discovery of young in the nest appear in a 

 tabulation by DuBois (1935) for Teton County, Montana. May 22 

 appears to be the earliest, other dates being May 26, 27, and 31. 

 In the same state for Chouteau County, A. A. Saunders (1921) has 

 May 23 as the first day on which young were found, but, he adds, 

 "the young were already half grown," which suggests a hatching date 

 as early as May 18 or 19. 



Care of the young is assumed by both male and female, especially 

 during the nestling period. "The female brooded most of the first 



