66 U. S. BUREAU OF FISHERIES 



benefit to the nonkillable seals, as at present the drive from these 

 rookeries is the longest and hardest on either island. 



BULLS 



Each year, as the seal herd increases in size, it becomes more difficult 

 to make accurate counts of bulls on the larger rookery areas. By mak- 

 ing actual counts on the smaller congested areas of the larger rookeries, 

 however, it is possible to form a very close estimate of the number of 

 bulls on the entire rookery. The counts and estimates thus made are 

 sufficiently accurate for all practical requirements. 



Owing to the impossibility of making accurate counts of the larger 

 rookeries, the entire harem and idle bull census should be considered 

 only as a close estimate. 



The reserving of sufficient 3-year-old males for breeding require- 

 ments is very necessary to provide for a maximum growth of the herd. 

 It is essential, therefore, to continue to take a census or to estimate 

 the number of breeding bulls on hand each year. This is the only way 

 to determine the approximate average harem, which must be main- 

 tained at a proper size if the herd is to increase at the maximum rate. 



There also must be sufficient mature young bulls to take care of the 

 virgin 2-year-old females. Accurate observations alone can determine 

 whether there are sufficient bulls of tliis class. It is to the best interests 

 of the herd to reserve a few more males than actually are required for 

 breeding purposes. 



Polovina and Polovina Cliffs now form one continuous rookery. 

 Harems now cover that part of the available waterfront which up to 

 this year separated the two rookeries. 



On the North and East Cliffs rookeries, St. George Island, harems 

 cover the entire area between the waterfront and the high cliffs. 

 There are therefore no idle bulls in the rear of these rookeries. The 

 idle bulls are found only on the adjacent hauling grounds. 



A pure albino 5-year-old male seal was observed on Reef hauling 

 grounds throughout the latter part of the season. Its presence was 

 not noted in the previous years of its existence. The animal was not 

 killed, as it was thought advisable to leave it for further observa- 

 tion, should it live long enough to hold a harem. It appeared to have 

 difficulty in seeing and therefore had a hard time keeping up with the 

 other animals when disturbed or in drives. 



