BOGOSLOF MURRES 331 



The fog was thick all the way so thick that we could 

 see only such birds as actually passed over or very 

 close to the ship and yet the compass showed that their 

 course was laid direct for the volcanoes. How they 

 found their way is a mystery not yet satisfactorily ex- 

 plained. As we neared the islands their numbers in- 

 creased until the air was full of them, coining from differ- 

 ent directions and all moving in straight courses to the 

 cliffs. When finally the ship hove to, and we set out in a 

 small boat for shore, the water was dotted with them, and 

 some allowed us to approach so near that we almost 

 caught them in our hands. On landing, the sea-lions be- 

 came at once the objects of absorbing interest, but still we 

 could not help noticing the great swarms of murres which 

 continued coming to the cliffs. When one of our col- 

 lectors fired his gun the multitudes that shot out into the 

 air and circled round the island formed a dense cloud 

 which cut off the light and made a roaring noise so loud 

 that it drowned even the bellowing of the sea-lions. And 

 yet, after their departure, the cliffs seemed as completely 

 peopled as before so inconceivably great were their 

 numbers. 



In the case of most forms of animal life the increase of 

 the species is checked by enemies and by the limitations 

 of the food supply, but in the case of the murres in Ber- 

 ing Sea, enemies are scarce, and the ocean seems to pro- 

 vide an inexhaustible store of food, so that the only 

 apparent check to extravagant multiplication is the limit 

 of available nesting places. And since the bird's require- 

 ments in this direction are easily satisfied a shelf or point 

 of rock three or four inches square answering every need 

 the numbers already attained are almost beyond belief. 



Two kinds of murres are common in Bering Sea, but 

 the six specimens obtained by me on Bogoslof, August 1 i, 

 1891, and also the six secured by Dr. A. K. Fisher on 



