May, 1920 AUTOBIOGRAPHICAL NOTES 101 
point with pardonable pride to the organization of some important lines of 
research, to the consummation of some important projects, and to much good 
work in several lines of biologic research. Assured of its past, it may look 
forward with confidence to larger service and to a still greater measure of 
usefulness in the future. , 
In 1910, through the establishment of the Harriman fund, Dr. Merriam 
was enabled to relinquish all governmental work and to devote his undivided 
attention to scientific investigations of his own choosing, thus attaining a 
goal which many scientific men look forward to but rarely realize. In the 
Biological Survey, which he founded, and the affairs of which he so long and 
ably conducted, he has left a fitting monument. After his resignation | was 
appointed Chief of the Survey, June 1, 1910, which position I retained till 
December 1, 1916, when I resigned because of failing health, my successor 
being Mr. E. W. Nelson. 
Washington, D. C., February 4, 1919. 
THE EXISTENCE OF SEA BIRDS A RELATIVELY SAFE ONE 
By JOSEPH GRINNELL 
(Contribution from the Museum of Vertebrate Zoology of the University of California) 
HE frequent reports of numbers of sea birds found along ocean beaches 
following storms are usually so worded as to lead the reader to infer 
that the life of oceanic birds is a markedly hazardous one. That quite 
the opposite is the case, under conditions undisturbed by the human factor, 
in comparison with most land birds is shown by a consideration of the breed- 
ing rates of the various species in question. 
In no sea bird that frequents the North Pacific Ocean, insofar as I am 
aware, is more than one brood reared each year. Furthermore, with the ma- 
jority of pelagic species, but one egg is hatched each year. Among these slow 
breeders are all of the albatrosses, all the petrels, the shearwaters, the fulmars, 
the auklets, the murres, most of the murrelets, and the puffins. With the 
Pigeon Guillemot and the kittiwakes, two eggs is the rule; while with most 
gulls, which, significantly, are much more littoral, three is the average number. 
It is an accepted biological principle, I beleve, that the rate of repro- 
duction in any animal is somewhat in excess of sufficiency to meet the maxi- 
mum probabilities of casualty in that species. Population may be supposed 
on an average to remain constant from year to year, even though we may ob- 
serve fluctuations above or below the mean. Thus, in the ease of the Fork- 
tailed Petrel, in which species but one egg is laid each year, the population 
of the species is raised not more than 50 per cent at the end of the breeding 
season—each two birds becomes three. But, by the beginning of the following 
nesting season, the population is (because of the average maintained norm) 
back to what it was a year previously. In other words, starting with 20 birds 
in April, there will be 30 (or less) by July; but by the April following, 10 of 
