CALLIOPE HUMMINGBIRD 425 



ground and rock mosses, 10 per cent; tree mosses, 5 per cent; spider webs 

 and i3bers of insect cocoons, 1 per cent ; miscellaneous material, 4 per cent. 



The "shell" of the nest is formed principally of ground and rock mosses 

 mixed with more or less plant down, strongly bound together with cocoon 

 fibers, especially at the rim. Many species of moss are utilized, but generally 

 only one kind is used in an individual nest. In many cases black fibrous tree 

 moss also is used. This part of the nest contains the "miscellaneous material." 

 In the fourteen nests examined this included conifer needles, grass, aspen bark, 

 rotted wood, feathers (from the birds themselves), small leaves, and pieces 

 of spider and insect skeletons (Diptera, Coleoptera, and Hymenoptera ) . 



The exterior of this framework is thickly covered with gray or greenish 

 lichens of the kind occurring on the tree in which the nest is placed. The 

 pieces are bound to the moss by shreds of insect webs and cocoons, or by 

 fibrous tree moss. The main body of the nest, within the sustaining framework, 

 is composed of a thick, soft layer of various kinds of plant down, firmly com- 

 pacted to form the interior cup. This down retains its shape without being 

 bound with any other material. 



Second year additions to a nest are composed mainly of down. Often the 

 only added material is a thick layer of down in the bottom of the cup, and 

 a thinner one on its sides. This method of addition decreases the depth of 

 the cup about a quarter of an inch. In other cases, the rim of the nest is 

 heightened also. If this is done, a new layer of lichen is added to the out- 

 side of the nest, making it impossible to determine, from the appearance of the 

 exterior, how many years the nest has been used. 



The foregoing paragraph indicates the methods employed by hum- 

 mingbirds in repairmg, or adding to, a last year's nest, a common 

 practice among some species. But often, with this and other species, 

 an entirely new nest is attached to or built upon the remains of a 

 last year's nest; in this case the old nest can be easily recognized by 

 its faded appearance. A series of two, tliree, or even four such nests, 

 perhaps built during successive seasons, may occasionally be seen. 

 Ridgway (1892, pi. 1) shows a cut of a 4-story nest of a calliope 

 hummingbird. 



Eggs. — The calliope hummingbird lays the usual set of two eggs. 

 These are like other hummingbirds' eggs, pure v/hite, without gloss, 

 and varying in shape from oval to elliptical-oval. The measurements 

 of 45 eggs average 12.1 by 8.3 millimeters; the eggs showing the four 

 extremes measure 13.0 by 9.6 and 10.7 by 7.4 millimeters. 



Plumages. — No information seems to be available about the devel- 

 opment of the Juvenal plumage, or about the early nest life of the 

 young calliope hummingbird. In the full juvenal plumage, just after 

 leaving the nest, the young male is practically indistinguishable from 

 the adult female, as it still has the throat more or less streaked or 

 spotted with bronzy brownish or dusky and with no sign of any 

 purple in the gorget; I have seen birds in this plumage up to the 

 first of Jnly ; some, but not all, young males have rather more rufous 

 in the tail than the adult female has. Specimens taken in August 



