SPRAGUE'S PIPIT 55 



In a cavity thus formed the nest was placed. Being six inches deep and six 

 inches in diameter, the cavity was much too large for the purpose. The birds 

 had met the situation, however, by filling in the unwanted space to a depth of 

 three inches with dead grass, thus forming a kind of platform beside the nest 

 which undoubtedly was found useful during nesting operations. The nest proper 

 was composed of dried grasses two to six inches long. Unlike the filling, it was 

 packed and woven into a firm structure. The rim was placed level with the 

 tilling three inches from the bottom, and the interior measured (after the young 

 had left) three inches in diameter and about one and one half inches deep. It 

 occupied the position farthest from the entrance, with one side resting against 

 the earth wall of the cavity. Overhead, the nest was shielded by a frail roof 

 of dead grass anchored in the plants that stood at the edge of the depression. 

 The entrance hole was barely more than two inches in diameter, and as the 

 grass filling was interioosed between it and the nest, the latter could be seen 

 only from a very low angle. This arrangement thus aided concealment. 



Eggs. — The set of eggs seems to consist generally of either four or 

 five ; rarely a set of six is laid ; reported sets of three are probably in- 

 complete. The five eggs found by Dr. Allen (1874) "were rather 

 long and pointed, being 0.90 of an inch in length by 0.60 in diameter. 

 The ground color is dull grayish white, thickly and quite uniformly 

 covered with shall blotches of purplish brown, giving to the eggs 

 a decidedly dark purplish tint. In color the eggs thus somewhat 

 resemble those of AntJius ludovicianus.^^ 



The Macouns (1909) quote Walter Kaine as saying that "they are 

 something like eggs of the prairie horned lark but are smaller. Some 

 have a pale buff ground, others greyish-white ground, minutely 

 speckled with buff and purplish grey. The eggs can be easily told 

 from small prairie horned lark's eggs by the fine dark brown lines at 

 the largest end of the eggs." 



There is a set of four eggs in the Thayer collection in Cambridge. 

 These are ovate and only slightly glossy ; the ground color is grayish 

 white ; and they are evenly sprinkled over the entire surface with small 

 spots and fine dots of pale olive-brown. 



The measurements of 44 eggs average 20.9 by 15.3 millimeters ; the 

 eggs showing the four extremes measure 22.6 by 15.7, 21.0 by 16.7, 19.2 

 by 14.0, and 20.5 by 13.5 millimeters. 



Young. — The incubation period for Sprague's pipit does not seem 

 to have been learned. Mr. Harris ( 1933) found that the female did all 

 the brooding over the young ; probably she assumed all the duties of 

 incubation also. The young that he watched remained in the nest 

 for at least 10 or 11 days : 



The work of caring for the young in the nest appeared to be assumed entirely 

 by the female. The male was never observed to take part in it. Indeed, the 

 male was detected near the nest only twice, and on both these occasions the 

 female drove it away. The male had ceased its singing rather abruptly about 

 the beginning of August, and was not heard during the course of this nesting. On 

 August 24, the day the nest was found, it was seen with one well-grown young 

 bird, which was presumed to be of the first brood. From this it was concluded 



