Jan. ,1911 COLLIJCTINd SOCoRRO AND BLACK Pin'RlJL.S IK I.OWIvR CALIFORNIA .LI 
iiionly. A favorite locality for burrows was in the loose loamy soil on the slope of 
the saddle at the east end of the island. A few were found nesting on a steep, 
treacherous, open cliff on the we.stern exposure. Here the birds had burrowed in 
under loose, flat rocks; and a tunnel enlarged sufficiently to admit one’s hand would 
usually bring the entire immediate vicinity down on one’s head. This mode was 
given up after a few attempts at dodging boulders and picking a “non-cactus” 
place for a foothold. 
In the'amphitheatre the nests were much more acce.ssible, some burrows being 
not more’, than ten inches in length, but others were dug out where the egg was de- 
posited five feet from the entrance. The longest burrows were zig-zag tunnels 
around loose boulders in the softest soil, and took considerable effort before the end 
was reached. The nests themselves were usually composed of matted grass and 
feathers with an under layer of sticks and pebbles. I found some with merely a 
scratched-out depression in the soft earth, with finely powdered loam heaped 
around the rim of the hollow to hold the eggs. The burrows showed but little 
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signs of the incoming of the birds as compared with those of the Murrelets. I often 
found large caves, one measuring at least fifteen feet stjuare, carpeted with soft 
earth which was .sensitive to impressions. The floor of one large cave was a mass 
of tiny overlapping Alurrelet tracks. In this cave the Murrelets burrowed back in- 
to almost inaccessible crannies and crevices, where the}^ were easily found, but hard 
to reach. They probably use these caves as convenient roosting grounds or for 
nocturnal love walks, as Imt few of the burrows in such localities were found to be 
nesting sites, and none contained more than fragments of faded egg shells. I used 
a candle for locating eggs in one particularly deep cave, and lying prone shoved the 
light down the shaft ahead of me until for want of oxygen it flickered and failed. 
This cave was a tight fit and my companion was luckil}" there and pulled me out liy 
the heels. 
The sharp, thorny, buckthorn bushes completely obscure the Inirrows of the 
Petrels on the brushy area^ and offer great protection to them also, as our gloves in 
shreds were witnesses after a few hours work. Pkirly in the season when the islands 
were visited, two birds were usuallv found in a burrow; later, brooding birds only. 
