BROAD-TAILED HUMMINGBIRD 391 



sycamores 3 to 20 feet above ground, and two were in pines 20 and 

 30 feet from the ground. 



The six nests of the broad-tailed hummingbird in the Thayer 

 collection in Cambridge show about the same range of variation in 

 size, shape, and make-up as those described by Bendire above. One 

 nest, however, is decidedly smaller, measuring only ll^ inches in 

 diameter and 1 inch in height externally ; the walls are very thin and 

 the cup is very shallow; it is made of the usual materials, mixed 

 with the winged seeds of milkweed or thistle. Another nest ig 

 worthy of mention, as illustrating camouflage to match its surround- 

 ings; it was built on a sycamore branch, composed of sycamore or 

 willow cotton, and was decorated on the outside, almost completely 

 covered, with pale gray and buff lichens, producing a soft, buffy 

 effect to harmonize with the branch that held it. 



Eggs. — The broad-tailed hummingbird lays almost invariably two 

 eggs ; I have no record of more or fewer. These are like those of other 

 hummingbirds, pure white, without gloss, and about elliptical-oval 

 in shape. The measurements of 62 eggs average 13 by 8.8 millimeters ; 

 the eggs showing the four extremes measure 14.5 by 9.9, 13.8 by 10.0, 

 11.9 by 8.4, and 12.2 by 7.9 millimeters. 



Yoimg. — The period of incubation is probably about 14 days, as 

 with other related species. Incubation is performed wholly by the 

 female, and she takes full care of the young; she is a brave and 

 devoted mother. The young are fed at first on regurgitated, semi- 

 digested food, but as they grow older they are given an increasing 

 amount of minute insects; they are fed at more or less irregular 

 intervals. Dr. Linsdale (1938) says of a nest that he watched: "At 

 10 o'clock I saw the female go to the nest and feed 5 times, the last 

 for only a short period, and then brood. The first thrust was deep 

 down the gullet of the young, and then the bill was withdrawn grad- 

 ually. At 10 : 12 the female was off the nest. At 10 : 19 it returned 

 and fed 4 times and brooded. Each feeding required between 5 and 

 10 seconds. It was not more than a minute from the time of arrival 

 to time of settling on the nest. The bird faced at least 3 directions 

 while brooding but always stood on the north rim to feed. Wlien it 

 left at 10 : 27, there were clouds and a cold wind. At 10 : 31 it re- 

 turned directly to the nest and began to brood." 



Plumages. — I have no data on the development of the juvenal 

 plumage in the nestling broad-tailed hummingbird, but it probably 

 does not differ materially from that of the rufous hummingbird, 

 described under that species. 



Ridgway (1911) describes the young male, in juvenal plumage, 

 as "similar to the adult female but feathers of upper parts (espe- 

 cially rump and upper tail-coverts) indistinctly margined terminally 



