NUTTALL'S POORWILL 189 



eggs on a steep hillside in some rough pine brakes at his ranch near 

 KJnowlton. In this unfrequented place the eggs were fully exposed 

 on the bare earth amidst the pines. On June 28, we went together 

 to the place intending to photograph the eggs, but they had been 

 already removed by the bird." 



Eggs. — The two eggs of the poorwill are generally said to be 

 pure white, but Bendire (1895) says that the color is not pure white 

 and that "on close inspection it can readily be seen that it is a 

 delicate cream, with a faint pinkish tint which does not perceptibly 

 fade. Eggs in the collection taken more than twenty years ago still 

 plainly show this peculiar tint. The eggs are unspotted as a rule, 

 but an occasional specimen shows a few faint, darker shell markings 

 around one end, which are barely perceptible to the naked eye, and 

 which fade considerably in time." 



In shape the eggs vary from oval to elliptical-oval; and they are 

 only moderately glossy. The measurements of 50 eggs average 26.3 

 by 19.9 millimeters; the eggs showing the four extremes measure 

 28.9 by 19.8, 27.5 by 21.6, 22.1 by 19.3, and 24.6 by 18.1 millimeters. 



Young. — The period of incubation does not seem to be definitely 

 known. Dr. Wetmore (1932) says: "Both birds are said to assist 

 in incubation. When disturbed about the nest, they tumble about 

 and with widely opened mouths make a loud hissing sound terrify- 

 ingly like the hissing of a snake." 



Robert B. Rockwell writes to me that he found a female with 

 two young "as large as an ordinary week or ten days old chick. 

 They were squatting perfectly motionless on the ground, about a 

 foot apart, each in the shadow of something. Their feathers were 

 quite well developed. They made no move when I picked them up, 

 but opened their eyes when I put them down again." 



Plumages. — Elmer C. Aldrich (1935) describes the downy young 

 of the dusky poorwill, less than a day old and about 2^/2 inches long, 

 as covered with a rich buff down. Ridgway (1914) describes the 

 downy covering of a young nuttalli as "vinaceous-buff, paler on un- 

 derparts." Two small partially downy young in my collection are 

 showing the growth of the first plumage on the forehead, crown, 

 nape, back, and scapulars; these feathers are dull buffy white, mi- 

 nutely sprinkled with grayish, and have small spots and narrow bars 

 of black; the new feathers on the underparts and flanks are dull 

 white, indistinctly barred with dusky; the wings are less than one- 

 third grown, and the tail is just sprouting. 



Ridgway (1914) says of the young in juvenal plumage: "Not essen- 

 tially different from adults, but markings in general less sharply 

 defined, especially on underparts, and throat patch buff instead of 

 white." 



