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 Jan., 1911 THE PALLID WREN-TIT 31 found nesting in the sage (Artemesia) of the lowland country. The nest, in both location and construction, is not in the least what the uninitiated oi51ogist would expect in this type of bird. The first one I ever saw was building and, no birds being present, I felt sure it must belong to some kind of flycatcher that had es- caped my notice, so closely did it resemble certain types of nests of the Traill Flycatcher (Empidonax lraill[ lralh') that I have found. It was a perfectly typical nest, both in location and construction, being placed about one foot from the ground in the crotch of a live-oak bush that stood in a dense thicket of the same. It is built externally of silky plant fibres, fine strip of bark and fine dead grass, the lining being mostly of horse hair. The measurements are externally four inches in diameter, by a little less than three inches in depth; internal dimensions being two and one-quarter inches wide, by one and three-quarters deep. I have seen one nest as high as five feet above the ground, but this is most unusual, three feet up being considerably higher than the average. The eggs in all the nests that I have examined were invariably four in nmnber to the set. They are most attractive in appearance, being greenish blue in color, without markings of any kind. In shape they are a rounded-oval, as a rule, aver- aging in size about .74X.57 inches. The female appears to commence coveting the eggs much of the time before the set is completed, as on two occasions I have found the bird sitting on three eggs, to which a fourth was added on the day following. Even under these cir- cumstances the bird is exceedingly loath to leave the nest, and after incubation com- mences it is necessary to startle her very considerably, or remove her by hand, in order to examine the contents of the nest. She will then very often remain in the same bushl scolding in'a low, harsh ch-ch-ch, continuously and very rapidly re- peated. This usually brings up the male, who looks over the situation for a moment or two and then returns to his singing, feeling apparently not the least sympathy with the vigorous protests of his mate. I have noticed this habit in sev- eral other varieties of birds, and have often asked myself if it might not, instead of lack of sympathy, be another method of endeavoring to draw the attention of an intruder away from the nest. COLLECTING SOCORRO AND BLACK PETRELS IN LOWER CALIFORNIA By .PINGREE I. OSBURN XVITH TWO PHOTOS HIS Genus of birds (Oceanodroma) is to the author one of unusual interest. Every available opportunity that has come my way for five years past has been made use of to become better acquainted with sea fowl in general and the Petrels in particular. For this reason the Los Coronados Islands were visited several times in recent years, each stay'consisting of from one day to two weeks. While I was disappointed by not finding these'particular birds on all my trips, the entire number of days ashore in active work among their burrows would number a satisfactory total. The two trips of most importance'were on July 3, 1909 (the third trip), and June 19 of the present year (the sixth trip). The first was in company with Mr. Willis Ritchie, and the second with Mr. A. B. Howell. I wish to hereby acknowl-