50 BULiLETIN 113, UNITED STATES NATIONAL. MUSEUM. 



Eggs. — The set usually consists of two eggs, rarely three, and often 

 only one. The eggs are usually about ovate in shape, and in a gen- 

 eral way resemble those of the common kittiwake, though they aver- 

 age lighter in color and are somewhat less heavily spotted. The 

 ground color is bluish white, buffy white, creamy white, or even 

 pure white. The markings consist of spots, blotches, or scrawls scat- 

 tered irregularly over the egg or occasionally concentrated m a mass 

 at the larger end or in a ring around it. 



These markings are in various shades of drab, lavender, or lilac, 

 overlaid with various shades of brown, mostly the lighter shades, 

 but sometimes as dark as " bister " or " sepia." The measurements 

 of 43 eggs, in various collections, average 55.8 by 40.9 millimeters; 

 the eggs showing the four extremes measure 66.5 by 45 and 50 by 

 37 millimeters. 



Young.— Mt. Elliott (1880) says: 



Both parents assist in the labor of incubation, which lasts a trifle longer 

 than the usual time — from 24 to 26 days. The chick comes out with a pure 

 white downy coat, a pale v/hitish-gray bill and feet, and rests helplessly in the 

 nest until its feathers grow. During this period it is a comical-looking object. 

 The natives capture them now and then to make pets of, always having a 

 number every year scattered through the village, usually tied by one leg to a 

 stake at the doors of their houses, where they become very tame ; and it is not 

 until fall, Avhen cold weather sets in, that they become restless and willingly 

 leave their captivity for the freedom of the air. 



Plumages. — The downy young are not distinguishable from those 

 of the Pacific kittiwake, being covered with white down without 

 spots. So far as I have been able to learn from the available mate- 

 rial the molts and plumages are similar to those of the comimon 

 species. There is no ju venal plumage, the young bird going directly 

 from the downy stage into the first winter plumage ; in this plumage 

 the young bird has a well-marked, dark, cervical collar, considerable 

 dusky about the eyes, and a mantle variegated with grayish-white 

 tips ; but it has no black on the wing coverts, secondaries, or tail, as 

 in the common kittiwake. These dark markings are usually wholly 

 or partially lost during the first spring, but they are sometimes re- 

 tained through the summer by failure to molt in the spring or by a 

 partial renewal of feathers in sympathy with the first winter plum- 

 age. At the first postnuptial molt (in August) the adult winter 

 plumage is assumed. 



Adults have a complete postnuptial molt in August and ap- 

 parently a partial prenuptial molt early in the spring. Winter 

 adults have the cervix and the auriculars washed with plumbeous. 

 In the adult nuptial plumage this is one of the most beautiful birds 

 in Bering Sea, where we learned to recognize it by the short, yellow 

 bill, bright red feet, dark mantle, and wings. 



