18 The Bird Rock Group. 



haunts of the birds during the egg-laying season. It is stated 

 that some twenty years ago 30,000 dozen Murres' eggs were gath- 

 ered annually on the Farallone Islands and sold in the San Fran- 

 cisco markets. As a result of this wholesale robbing, the birds 

 decreased in numbers so rapidly that the United States Govern- 

 ment forbade their further molestation. It is greatly to be hoped 

 that the Canadian Government will soon take steps to afford simi- 

 lar protection to the Murres of Bird Rock. 



Two species of Murres inhabit Bird Rock, the Common Murre 

 (Urici troile) and Briinnich's Murre (Uria lomvia). To the 

 casual observer the differences distinguishing them are not at 

 once apparent, and the presence of two such closely related 

 birds, of similar habits, in the same place, is an interesting illus- 

 tration of the retention of specific differences under circumstances 

 unusually favorable for interbreeding. 



The Common Murre has a longer, more slender bill and 

 browner head than Briinnich's Murre, which has a relatively 

 short and thick bill with the basal edges of the lower mandible 

 grayish and swollen, and the head dark. The downy young of 

 the Common Murre are sooty black, sprinkled with white; those 

 of Briinnich's Murre are decidedly browner. The Common 

 Murre breeds in the North Atlantic from Bird Rock and the 

 British Islands northward. In winter it ranges southward to 

 the coasts of Massachusetts and northern Africa. 



Briinnich's Murre breeds from Bird Rock northward, but is 

 rare in the eastern Atlantic. In winter it is found occasionally 

 as far south as New Jersey, and, sometimes it reaches the interior 

 states as far west as Michigan, by way of the St. Lawrence River 

 and the Great Lakes. 



Some Murres have a white ring around the eye extending 

 backward in a white stripe behind it. They are known as 

 "Spectacled Murres," but whether they constitute a distinct 

 species, or are merely an individual variation, is as yet unknown. 

 One individual of this kind is shown in the group. 



Razor-billed Auk (Alca torda). The Razor-bill is the nearest 

 existing relative of the extinct Great Auk, which it resembles in 

 general appearance, but from which it differs in possessing the 

 power of flight. This species lays its single egg, which is more 

 elliptical than that of the Murres, in natural cavities or other- 



