16 BULLETIN 16 7, UNITED STATES NATIONAL MUSEUM 



pairs a short distance apart and were probably the product of two 

 females. The eggs are usually elliptical-ovate or elongate-ovate in 

 shape, but a few are ovate and rarely one is cylindrical-ovate. The 

 shell is smooth or very finely granulated, with little or no gloss. 

 The ground color is dull white or creamy white. The eggs are 

 prettily marked and sometimes nearly covered with spots, blotches, 

 and splashes of bright browns. Generally they are boldly and ir- 

 regularly blotched and spotted, sometimes sparingly or finely 

 spotted, with dark browns, such as "chestnut", "liver brown", or 

 "chocolate" and more rarely with "russet" or "cinnamon-brown"; 

 they are often washed with one of the above browns and many have 

 underlying spots in shades of "Quaker drab." Very rarely one is 

 nearly or quite immaculate. The measurements of 52 eggs average 

 71.3 by 48.6 millimeters; the eggs showing the four extremes meas- 

 ure 83.5 by 50, 76 by 53, 62.5 by 50.5 and 71.3 by 43.7 millimeters.] 



Young. — When the nature of the vulture's food is considered, it 

 seems almost inevitable that the young birds, in their earlier days, 

 be fed by the process of regurgitation. Thus, one of the first as- 

 sociations that the nestlings learn is that of the odor of decompos- 

 ing animal matter with appetite and good digestion. 



A. G. Lawrence, writing from Winnipeg, Manitoba, to Mr. Bent, 

 describes the process, which he watched from a blind on the side of 

 a cliff. "Both young rushed toward the female parent with wide- 

 spread wings. The first to reach her thrust its bill well into the 

 parent's gullet, the old bird stretching out low over the rock to 

 facilitate the exchange of regurgitated food. The feeding process 

 was carried on so vigorously that it resembled a tussle, both birds 

 swaying their heads up and down and from side to side and balancing 

 themselves by raising their wings." 



As these young birds "were fully grown, but unable to fly", this 

 method of feeding may continue through the major portion of their 

 protracted life as nestlings. Lawrence continues: "The young spent 

 much of their time sunning themselves on the rocks outside the 

 nesting cavity. They continually exercised their wings, spreading 

 them out to their full extent whenever the sun shone and closing 

 them when a cloud cut off its rays. They stood with backs to the 

 sun, and their wings immediately responded to its warmth." 



Thomas H. Jackson (1903) estimates the period of incubation as 

 "very close to thirty days, possibly a day more or less" and "the 

 period between hatching and flight eight or nine weeks." In the case 

 of a nest under the observation of C. J. Pennock (MS.), these periods 

 were somewhat longer; the incubation lasted about 41 days, and at 

 the end of 74 days the young birds "had not been away from the 

 near proximity of the site and had not flown at all." 



