64 
BULLETIN OP THE UNITED STATES FISH COMMISSION. 
tlie belief that, on the 'lohole, a bull i.s able to take care of as many females as lie can 
keep around him. There is undoubtedly great individual differences in this respect, 
Some bulls being stronger than others, but 1 think it can be safely asserted, as a rule, 
that the procreative power of the bull is in direct proportion to his general physical 
strength. 1 think it also sound to assume that, as a rule, a bull physically strong 
enough to live through the winter gales and the vicissitudes of his winter wanderings 
and to return to his place on the rookery is ;dso strong enough to fulfill his duty there. 
I have pui'iiosely enijihasized “on the whole” and “as a rule,” because I can easily 
imagine individual cases of, for instance, accidentally castrated bulls, or old feeble ones 
who might have the good fortune to meet with unusually favorable conditions during 
their winter migrations, etc., and because I am quite willing to admit that a number of 
Such bulls may be found f)ii each rookery. These exceptions, however, do not materially 
alter the above propositions as relating to the whole population of the rookery. 
The train of reasoning Avhich led me to the above conclusions is as follows: Some 
of the most noteworthy of my observations this summer on the Commander Islands 
establish the facts (1) that the decrease in the killable seals was most marked on Cop- 
per Island; (2) that there was a full comi)lement of pups as compared with bi'ceding 
females on both islands; (3) that there was an ample supply of bulls, old and young, on 
Copper Island, while on Bering Island they were much less numerous as compared with 
the number of females. I was informed that the latter condition was not peculiar to 
the present year (1895) alone, and it is also particularly mentioned in Mr. Crebnitski’s 
report for 1803. It would therefore seem as if the different proportions between the 
sexes on the two islands have had no visible influence upon the number of pups born- 
The soundness of the above deductions may receive corroboration, or the reverse, 
by observations on the South Rookery on Bering Island in 189(). On that rookery 
the disproportion between the two sexes was excessive in 1895. According to reliable 
information, the number of bulls on the whole rookery did not exceed five.' Judging 
from what I saw of this rookery during two visits, I should place the number of 
breeding females at about fiOO, possibly only 509. It would be a comparatively easy 
matter to observe this year whether the number of ])ups born be very markedly small 
in ])roportion to the number of females hauling out. 
On the large rookeries it is difficult, if not impossible, for various reasons, to 
correctly estimate the average ]>roportion between the bulls an<l the females, and par- 
ticularly so on Bering Island, l)ecaaise the bachelors to so great an extent haul up 
between the breeding females. Mixed in among the latter in this way, it is next to 
impossible at long range to say, with any approach to accuracy, what the proportion 
between these two classes is.'^ In general, the difficulty lies in the fact that the 
individual harems difl'er so greatly in size. Thus, during the visit to Kishotchnaya 
Rookery, Bering Island, on July 9, Mr. Grebnitski counted several harems which 
contained all the way from 12 to 93 females, or more. But there is still another 
serious difliculty, which is due to the constant going and coming of the females, so that 
1 When I visited tlie rookery on August 17 the hulls had already left. It was rumored in the 
village that there had only heen one hull, hut Nikanor Grigorief, the natiAm in charge of the killing 
there, informed me that the actual numher was fiA^e. 
It is held hy some that the uatiAu-s ha.A'e such a marvelously keen eye and discriminating power 
as to enable them, at least, to make such an estimate. At one time I accepted this as a matter of faith, 
hut my experience last summer — to he detailed further on — has couvinced me that the natives are not 
particularly gifted in that res])ect. As a matter of fact, their estimates are about as much guessAvork 
as that of the Avhite pei>i)le, only that from their greater familiarity Avith the ground and the seals, 
they are apt to guess more closely. 
