LIFE HISTORIES OF JSTORTH AMERICAN DIVING BIRDS. 163 



liome, and one comparing the relative numbers of tlie birds of various species 

 frequenting a nesting place would be sure to consider the guillemots much fewer 

 in number than they really are; though on the edge of the ice, in the leads, 

 or on the open sea. he would realize his error. 



In a few localities, such as the southeast corner of Saunders Island, the bird 

 colony is composed almost wholly of the guillemot, and may be very large. At 

 this place, in a sharp reentrant in the cliff face, the rocks are evidently much 

 transected by numerous crevices v.hich furnish good nesting places near good 

 feeding grounds. Here whole bevies of guillemots fly in and out, and about, 

 in the nesting season, like bees hived in trees ; but instead of a steady hum, 

 there comes from the place the intermittent nervous, shrill, whistle much like 

 a squeal, that one learns to know so well along the Northland coasts. Similar, 

 almost pure colonies, of guillemots ai-e found at Crystal Palace Cliffs, at Cape 

 Parry, at Cape Atholl. and other places. Usually the guillemot nests lower on 

 the cliffs than do the other birds with which it is sometimes found, but in these 

 pure colonies it may nest far up, even to the tops of the highest cliffs. 



The nost is usually placed on a pile of broken debris well back in the crevices, 

 or on a shelf that seems safe. Rarely are the eggs so near the opening that one 

 can reach them without a " spoon " mounted on a rather long handle. The eggs 

 are generally two in number, but occasionally the Eskimo find three in a clutch. 

 The eggs do not exhibit such variations as do the eggs of TJria lotnvia lomvia, 

 different clutches being imiformly similar, though on some the blotching is 

 denser or more confluent, than on others. 



Eggs. — Mandt's guillemot lays ordinarily two eggs, occasionally 

 only one and, according to some writers, rarely three; probably sets 

 of three are accidental and the result of more than one bird's laying. 

 The nesting habits and the eggs do not differ essentially from those 

 of the black guillemot. I have never been able to detect any distin- 

 guishing characters in such eggs as I have examined, except that the 

 ground color is usually more greenish or bluish white ; so rather than 

 attempt to describe them, I will refer the reader to my description of 

 the eggs of the foregoing species. The measurements of 53 eggs in 

 various collections, average 59.6 by 39.5 ; the eggs showing the four 

 extremes measure 64.3 by 40.8, 62 by 42, 53.5^ by 38.5, and 55.6 by 

 37.6 millimeters. 



Yoimg. — Eegarding the young, Mr. Ekblaw writes: 



The young of this species develop rather slowly even for an altricial bird 

 in this latitude, more slowly than do those of the other northern species. 

 Since the birds appai*ently do not need to migrate south but require only open 

 water for their winter home, this slowness of development probably does not 

 endanger the birds. The young are fed constantly, both old birds having a 

 part in the feeding. Sea food is all the young get; almost exclusively their 

 diet is made up of shrimps, with which the water teems, though I have also 

 found in their crops the gastropod, that looks so much like the ordinary land 

 snail, and of which the eider is so fond. The young call insistently for food 

 from their emergence from the shell in their dark, dusky-brown down to 

 their first dip into the sea in their nice light suits of feathers to begin to 

 learn to find for themselves. They get into the water immediately from the 

 nest and do not return. They are attended by the parent bird for some time 

 after. They do not frequent the shore closely but stay fairly well out at sea, 

 5591G— 19— Bull. 107 12 



