98 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4TH SER. 
eleven hundred feet. The burrow had been driven through the 
fern and vine roots, that reinforced the soil, to the length of 
about four feet, where it terminated, fourteen inches below the 
surface, in a chamber lined with dry leaves. 
An egg, ready to be deposited, was taken from the oviduct 
of a bird shot on June 7 at sea about forty miles south of 
Albemarle Island. In April, off Iguana Cove, specimens were 
obtained showing considerable enlargement of the reproductive 
organs. 
During the breeding season they were active over the land 
at night. A party from the Academy in camp near the sum- 
mit of James Island on August 7 were kept awake by their 
incessant call-notes, uttered as the birds flew about just above 
the tree tops. At Indefatigable Island they congregated close 
inshore at dusk and circled over the water in loose flocks, from 
which individuals were constantly ascending in great spirals to 
the height of several hundred feet, when they headed inland. 
In the interior of the island they were particularly prominent 
during two hours after sunset and during two hours before 
sunrise, there being an evening flight to the land and a morn- 
ing flight away from it. While members of the Expedition 
were in the forest belt of Indefatigable Island in November, 
these petrels were frequently seen and heard in the nighttime 
as they flew overhead, but in January none were met with on 
the island, the land apparently having been forsaken for the 
sea. 
Usually their call-notes consist of four parts, “kee-kee-kee- 
koo,” the first three uttered quickly and the last drawn out. 
Sometimes the order is reversed and sometimes the “koo” is 
omitted. Occasionally the call-notes were heard in the day- 
time. A low guttural note was detected on one occasion when 
several hundred of these birds were following the vessel pick- 
ing up the turtle fat that had been thrown overboard. These 
petrels were very fond of this fat and it was used to decoy 
them within gunshot. Remains of pteropods and ccelenterates. 
were found in their stomachs. 
At sea their manner of flying did not differ from that of 
other representatives of the genus met with on the Expedition. 
In dead calms they flew near the surface of the water, and two: 
or three wing strokes were succeeded by a sailing flight of a. 
