NORTH AMERICAN BIRDS. 15 



markings are of two shades of lilac ; in some they are thickly spread 

 over the entire surface ; in others they form a circle about the larger 

 end. Mr. Bryant gives the average measurement of twenty-five sets of 

 two eggs each in Mr. Emerson's collection as, 61.6 by 41.4 mm.* Ex- 

 tremes in size, 66.5 by 41.5, 58.5 by 41 millimeters.f 



,^. 30. Urla troile (Linn.) [763.] 



Mnrre. 



Hab. Coasts and islands of the North Atlantic, southward on the coast of Nortn America in winter to 

 Southern New England; breeding from Nova Scotia northward. 



Like all of the Auks, Murres and Puffins, this species is eminently 

 gregarious, particularly in the breeding season. It is found in great 

 numbers throughout the Arctic Ocean and on nearly all the islands 

 north of Asia, Europe and America. On this side of the Atlantic it 

 breeds from Nova Scotia northward. 



Tens of thousands of these birds congregate to breed on the rocky 

 islands, depositing and incubating their single egg close to one another 

 on the shelves of the cliffs. The birds sit side by side, and although 

 crowded together, never make the least attempt to quarrel. Clouds of 

 birds may be seen circling in the air over some huge, rugged bastion, 

 forming a picture which would seem to belong to the imagination 

 rather than the realistic. They utter a syllable which sounds exactly 

 like murre. The eggs are so numerous as to have commercial value, 

 and they are noted for their great variation in ground color and mark- 

 ings. They vary from white to bluish or dark emerald-green in ground 

 color ; occasionally unmarked specimens are found, but they are usually 

 handsomely spotted, blotched, lined in various patterns of lilac, brown 

 and black over the surface. In some the marking are confused zigzag 

 lines that look like hieroglyphics. The eggs are large for the size of 

 the bird, measuring from 3. to 3.50 long by 1.95 to 2.10 broad; pyri- 

 form in shape. 



Y,^ 30«. Urla troile califomica (Bryant.) [t^s^-I 



California Murre. 



Hab. Coasts and islands of the North Pacific, breeding from California north to the Prybilof Islands. 



Mr. Emerson says that the California Murre is the most common 

 sea fowl on the Farallone Islands, and they do not seem to diminish in 

 number, notwithstanding the wholesale destruction of their eggs for 

 commercial purposes. The birds begin to lay by the middle or latter 

 part of May. Fresh eggs can be found as late as August. This is 

 due, more or less, to the many robberies to which the birds are sub- 



* 2.43x1.62. 



1 2.62x1.63, 2.30x1.61. 



