FUR-SEAL CENSUS, PRIBILOF ISLANDS, 1918. 123 
Facts obtained in 1918 from the 1912 branded males are of the 
ereatest significance in showing where this excess came from. The 
1912 seals were 6 years old this year. The supposition has generally 
prevailed in the past that males of this age were fully grown and able 
to hold harems or at least skirt the rookeries as idle bulls. But this 
is not true. The 6-year-old male is hardly half grown and resorts 
to the hauling grounds or elsewhere. He is not physically able to get 
anywhere near the breeding cows. 
These 6-year-olds were born the year the closed season became 
effective. Commercial killing was not done in 1912. So where does 
this great excess of full-grown males come from which has been found 
in 1916, 1917, and 1918? Obviously it can not be from the 6-year- 
olds. Likewise it can not wholly be from those animals which were 
born in 1910 and 1911, because they were only 6 years old in 1916 
and 1917, respectively, when there was a surplus. Therefore the 
closed season of 1912-1917 has not yet become effective upon the 
breeding grounds, and the surplus found in 1916 and 1917 and in 
large part in 1918 comes from those reserves spared from the killings 
of 1908 to 1911. The reserves then made for breeding Bunpese: were 
too large rather than too small. They provided the herd with so 
many bulls that the death rate of both pups and cows on land is 
far above what it should be. 
IDLE BULLS. 
Idle bulls were counted at the same time as the harems, and as the 
rookeries exist to-day this is a difficult task. There are so many 
nonbreeding males Ebout the rookeries that some plan had to be 
followed in segregating the idle bulls and that class variously known 
as quitters, young bulls,and half bulls. It has been learned that 
about three tiers of males just outside of the harems are stationary 
and hold their positions tenaciously. They are found spaced about 
as the harem bulls. Out beyond these there are more else however, 
which wander here and there endeavoring to find a place where they 
can get in close to the harems. The plan followed the past two 
years has been to classify those holding positions as idle bulls and all 
others as surplus bulls. This is a distinction which in some cases is 
hard to decide upon and the classes intergrade. However, it does 
not seem practicable to call all males about the rookery, not actually 
in possession of cows, idle bulls. ‘This might be done to obtain a 
figure for the total available reserve males except for the fact that not 
half of them are about the rookery. Large numbers give up hope of 
holding harems and go to the hauling grounds and to sea to cruise 
about the rookery margins. These must be estimated. Therefore 
the plan adopted seems best to follow. 
