[Illustration 271: Chimney Swift.] [Illustration: E. R. Forrest. NEST AND EGGS OF CHIMNEY SWIFT.] [Illustration: right hand margin.] Page 270 be seen to, one at a time, dive headforemost into the tops of chimneys. The nest is made of small twigs firmly glued to the sides of the chimney, or tree, and to each other, with the glutinous saliva of the bird, making a narrow semi-circle platform for the reception of their three to five white eggs which are deposited in May or June; size .75 × .50. 424. VAUX'S SWIFT. _Chætura vauxi._ Range.--Western United States, chiefly west of the Rockies; breeding north to British Columbia, and wintering south of the United States. Similar to the last but smaller (length 4.5 inches), and paler in color, fading to white on the throat. The habits of this species are like those of the eastern Chimney Swift, except that the majority of these species still continue to use hollow trees as nesting places. The eggs are just like those of the last bird. 425. WHITE-THROATED SWIFT. _Æronautes melanoleucus._ Range.--Western United States south of Canada, and chiefly in the Rocky Mountains, and in California ranges, north to Lat. 38°. A handsome species, 6.5 inches in length, with blackish upper parts and sides, and white throat, breast and central line of under parts, flank patches and ends of secondaries; tail feathers not spined or stiffened. These birds are fairly common in some localities within their range, but appear to be found only on high ranges or in their immediate vicinity. They nest in crevices and caves in the face of cliffs, making a nest similar in construction to that of the Chimney Swift but of weed stalks instead of twigs, and lined with feathers. They lay four or five dull white eggs, during June or July; size .85 × .50. [Illustration 272: White.] [Illustration: White.] [Illustration: 425--426.] [Illustration: White.] [Illustration: deco.] [Illustration: left hand margin.] Page 271 HUMMINGBIRDS. Family TROCHILIDAE Hummingbirds have been truly called "Winged Gems." They are the smallest of birds, the usual plumage being a metallic green with throat or crown patches of the brightest of iridescent shining red, orange, blue or violet. Their nests are marvels of architecture being compactly and intricately made of plant fibres and downy feathers ornamented in some cases with lichens. Their flight is accompanied by a peculiar buzzing sound produced by their rapidly vibrating stiffened wing feathers. Their food is small insects and honey both of which they get chiefly from flowers. 426. RIVOLI'S HUMMINGBIRD. _Eugenes fulgens._ Range.--Mexico, north in summer to southern Arizona where they breed at high elevations in the Huachuca Mountains.