86 THE FUR SEALS OF THE PRIBILOF ISLANDS. 
to indicate that the space unit for massed breeding grounds should be smaller. But 
for the underestimate which may therefore be involved on this account we can offer 
no correction. For the underestimate due to the early date at which the count was 
made we can make a rough estimate. The daily count on Lukanin rookery for the 
season of 1897 shows that between the 8th and 15th of July there was an increase of 15 
per cent in rookery population. This would increase the figures for 1895 as originally 
given to about 80,000, and after doubling for absentees the corrected total would 
be about 160,000 breeding females. The inclusion of the yearlings and 2-year-old 
females does not affect the total, as they were not present, and no allowance need be 
made for them. 
THE ESTIMATE REVISED. 
This total of 160,000 females, or giving to each female a pup and adding the 
estimated number of breeding bulls, making 325,000 “breeding seals and young,” is 
probably within 10,000 of the facts for the season of 1895. That it comes thus near 
the truth, however, is the result of accident rather than good management. The 
corrections which, in the light of subsequent experience, we have been able to make, 
are vital to its truth and change the results radically. The original results could not 
have been trusted alone, and were wholly misleading. 
THE IMPORTANT FEATURE OF THE ESTIMATE. 
The really important feature in the estimate of 1895 is the count of cows in which 
it originates. This was a distinct step in advance, in that it approached a rational 
basis. In the application of the unit of space to the rookeries not counted the method 
was unfortunate. The area of breeding ground was taken from maps in themselves 
imperfect, on which the rookery outlines were sketched by the aid of the eye. The 
rookery boundaries, as we have shown, are constautly changing as the season 
advances, and there being no definite landmarks to guide the observer, it is impos- 
sible that the outlines should be correctly located. The enumeration is therefore 
carried into the region of pure speculation and has only the value of the individual 
judgment of the person tracing the maps. 
It is fair to say, however, that nothing definite and exact was claimed for the 
census of 1895, as Mr. True’s own words, iu commenting upon it, will show. He says: 
“T do not think that any estimate can be made which will approximate the truth 
more than remotely,” and he continues to say that the chief use of such calculations is 
“the elimination of fanciful estimates of the number of seals.” 
MR. CROWLEY’S ESTIMATES FOR 1895. 
In leaving the estimates of 1895 it is necessary to refer to two other calculations 
of rookery population ‘made for the same year on a different basis. One of these is 
by Mr. J. B. Crowley, chief agent in charge of these islands. He finds, as he says, 
by actual count, a total of 99,936 breeding cows and 5,552 breeding bulls. When we 
make the necessary doubling of this estimate of cows and add the pups we have a 
total of about 305,552 ‘breeding seals and young.” Of the methods or details of this 
