Nov., 1909 BIRD NOTES FROM SAN LUIS OBISPO COUNTY 187 
intimation of danger and will appear on a point of rock some distance away, where 
she will be joined by her mate. Altogether we collected four sets of this species. 
Three of these were of three eggs each and one of two eggs. 
To secure two of these sets I had to swim thru a dangerous surf and land on 
jagged rocks; and the other two were on the top of rocky pinnacles which were all 
but inaccessible. The nests are placed on the lea side of a rock or projection 
sheltered from the prevailing wind, sometimes only a few feet above high water 
and at other times far above the reach of the flying spray. They are shallow cavi- 
ties in the rock or thin soil, thickly lined with sharp chips of rock evidently carried 
by the birds. Numerous scratches on the shells of the eggs show that they are 
frequently turned over by the birds who probably rely to some extent on the heat 
of the sun as an assistance in incubation. 
The birds subsist principally on mussels and limpets, and the ease with which 
they pry them from the rocks with the sharp, chisel-like bill furnishes a striking 
example of the natural law of adaptation to surroundings. The rocks around the 
nesting sites are covered with the shells of molluscs brought there by the birds. 
The statement that this species nests on gravelly beaches is erroneous as regards 
this locality. The first set of eggs was taken May 14, and was about half incu- 
bated. It was situated on a large flat-topt rock very difficult of access. There 
were breeding on the top of the same rock four pairs of Western Gulls and a colony 
of Brandt Cormorants; while on the precipitous sides were numerous nests of the 
Baird Cormorant; and in the caves at the base of the rock were two or three pairs 
of Sea Pigeons. The other three sets were taken on May 15, 16 and 17, respective- 
ly, and were on isolated rocks, the Oystercatchers being the sole inhabitants. 
In ground color - the eggs vary from grayish olive to greenish, spotted and 
blotcht with black and dark brown, with lavender shell markings. Thirteen eggs 
measure in inches: Maximum, 2.38X1.58; minimum, 2.08X1.45; average 
2.24X1.52. 
Los Angeles, California. 
A TIKE HISTORY OF THE NORTHERN BARD EAGLE 
By JOSEPH DIXON 
WITH FOUR PHOTOS BY ANNIE M. ALEXANDER 
I KNOW of no other Alaskan bird which seems to be more in keeping with the 
country than the Northern Bald Eagle ( Haliceetus leucocephalus alascanus) . 
While this bird is by no means restricted to the shore line of the Pacific be- 
tween the southern boundary of Alaska and the base of the Alaska Peninsula, still 
I believe that it may be truthfully stated that nowhere else does it find a more con- 
genial home or breed in larger numbers than along this thousand-mile stretch of 
islands, inlets and glacier-scoured coast. 
In size, this eagle is considerably the superior of its cousins in “the states’ ’ , 
since it is not uncommon to find female eagles that are more than thirty-seven 
inches in length, with a spread of seven feet and a half, or better. The males are, 
of course, quite a little smaller than the females and rarely equal the smaller fe- 
males in size. The largest female that I secured had a spread of seven feet and 
nine inches; length, thirty-seven inches. The males seemed to average about a foot 
less than this in spread, and were about thirty-six inches in length. I was inter- 
