168 BULLETIN 107, UNITED STATES NATIONAL MUSEUM. 
of Santa Cruz Island, one of the scenic spots of this region, we 
could row our boat far into the innermost recesses of picturesque 
winding channels and lofty, vaulted caverns of rock. A few cor- 
morants were disturbed near the entrance and numerous pigeon 
guillemots darted past us from within, as the reports of our guns 
frightened them from their nests in the darkest.corners. We were 
surprised to see also a number of house finches flitting about the 
high shelves and pinnacles of rock in the largest chambers, where 
they probably had nests within the reach of daylight. In such situa- 
tions the guillemots lay their eggs in various nooks and crannies 
about the walls and roofs of the caves, in cavities under loose rocks, in 
open situations on flat rocks or shelves, or even on the sandy floor of 
the cave, if beyond the reach of daylight and water; as they seem 
to find security in darkness, these caverns offer many suitable nesting 
sites. 
Much has been written about the nesting habits of the pigeon guil- 
lemot on the Farallone Islands, but the following extracts from Mr. 
Chester Barlow’s (1894) writings will suffice to give an idea of its 
normal nesting habits here and elsewhere: 
The “sea pigeons,” or pigeon guillemots, are among the most interesting of 
the birds. They are lovers of the sea and prefer the rocks near the surf, when 
not incubating their eggs. We were fortunate in discovering a rookery of these 
birds, and had it not been late for fresh eggs, a splendid series could have been 
secured. The hill, at the summit of which is the lighthouse, is very steep, and 
the cliffs at the top are more or less honeycombed with burrows in which the 
puffins and auklets nest. Farther down is a stretch of loose, shifting chips of 
rock, while near the bottom are numerous bowlders, some of gigantic propor- 
tions, under and between which are cavities in which the guillemots nest; As 
one approaches this rookery many of the birds are seen sitting upright, softly 
“ whistling,” but upon close approach those on the rocks take wing, while their 
mates flutter from among the rocks and join them. Then, by a careful search 
of promising-looking cavities, one may secure a nice series. 
No nest is constructed in which to deposit the eggs, but almost invariably the 
eges repose upon a collection of small granite chips or pebbles gathered by the 
birds. Both birds assist at incubation, and I have a male bird taken with a set 
of two eggs. The rookery described is not near the ocean, but many of the 
guillemots nest in holes in the cliffs above the sea. At any time groups of birds 
may be seen gathered on the rocks near the surf. I have noticed young ones so 
-close to the water that the spent force of a “roller” would almost wash them 
away. 
Mr. Milton S. Ray (1904) says of this species on the Farallones: 
‘These birds became more abundant every day during our stay, but they -did 
not begin to lay until the end of the first week in June. We found well- 
incubated single eggs as well as pairs; hence incubation must really have begun, 
although the majority of all the eggs we found were fresh. The nests, merely 
pebble-lined slight hollows, were located under projecting ledges, bowlders, or in 
spaces between piles of rocks, where they could be seen, not infrequently, from 
