AMONG THE WaTER-Fowxz 
presently arose to a crouching attitude, and ran back 
into what was left of the hole. Then I gave it-a 
toss into the air, and, after a little zigzag meander- 
ing over the grass and rocks, it seemed to get its 
bearings, flew down in its usual irregular manner to 
the water, and disappeared off to sea, without show- 
ing any inclination to return to the nest, nor did it, 
that we could see, during the day. 
We dug out a number of other burrows till we 
had seen enough to generalize the observations a 
little. We did not find more than one egg in any 
nest, and I do not know that any such instance has 
ever been recorded. Sometimes there were two 
birds in a burrow, but in these cases the egg had 
not been laid. ‘Two birds that I took in the act of 
incubation from different nests and kept as speci- 
mens proved to be males. Some observers have 
thought that the male usually incubates, but others 
are said to have found birds of either sex indiffer- 
ently thus engaged. 
The puzzle is what becomes of the other 
partner. Practically never is a Petrel to be seen by 
day about the breeding-grounds. At night, how- 
ever, the Petrels become active and noisy, twittering 
constantly, and flying to and fro from the sea. We 
cannot assume that the other is in some hole 
near by, for all the birds found are incubating. 
The fact also that the males incubate precludes the 
possibility of their deserting their mates, as is the 
case with the Ducks. Until something to the 
contrary is shown, we evidently must be content 
with the old theory that one bird of each pair flies 
out to sea during the night, leaving the other on 
126 
