NORTH AMERICAN BIRDS. 231 



Swallow. From four to six narrowly elliptical pure white eggs are de- 

 posited, ordinarily four. May and June are the nesting months, and 

 usually but one brood is reared in a season. A set of four eggs, col- 

 lected in the Adirondack region, Essex county, New York, June 

 27, measure .82 x .52, .81 x .52, .84 x .51, .82 x .50 ; a set of five taken in 

 Franklin county, Ohio, exhibit the following sizes: .79X.50, .80X.50, 

 .80X.52, .77x50, .79X.53. The eggs in a large series range from .74 

 to .86 in length and from .47 to .55 in breadth. 



424. Chsetura vauxii (Towns.) [352.] 



Vaux's Sivift. 



Hab. Pacific coast, from British Columbia south in winter to Guatemala. 



This is a lighter colored and smaller species than the Chimney 

 Swift. The habits of the two birds, however, are similar, except that 

 Vaux's Swift is said only to nest in hollow trees. In various regions 

 of Oregon and in Washington Territory this species is a common sum- 

 mer resident, where it breeds in May and June, fastening to the inside 

 walls of hollow tree trunks and stubs the half-saucer-shaped nest of twigs, 

 which is glued together with the bird's saliva. Four or five narrow- 

 elliptical white eggs are deposited, which have an average size of 

 .74X.50. 



428. Trochilus colubris Linn. [335.] 



Rnby-throated Hummingliird. 



Hab. Eastern United States to the Great Plains, north to Canada, south in winter to Cuba, Eastern 

 Mexico and Central America, to Uraguay. 



This is the only species of Hummingbird found east of the Missis- 

 sippi, where it is common and well-known. Its small size, iridescent 

 plumage, its marvelous swiftness of flight, and the architectural beauty 

 of its nest are the admiration of all. 



The eggs of the whole family of Hummingbirds, as far as known, 

 are white, unspotted ; rather elliptical than oval, and always two in 

 number. The only difference noticed are the relative variations in size. 

 The nests are generally saddled upon a horizontal branch, are cup-like 

 in shape, and are mostly made up of various kinds of soft vegetable 

 down ; in nearly all cases covered on the outside with a coating of 

 lichens or mosses. The nest of the Ruby-throated Hummingbird is a 

 miniature of the Blue-gray Gnatcatcher's. It is felted with a mass of 

 exquisitely soft, cottony, silky, or woolly substances, such as the down 

 from the stem of plants, and is artistically covered on the outside with 

 lichens. It is usually placed on a horizontal limb of a forest or orchard 

 tree. Several specimens before me are placed on branches that were 

 slanting, and the nests rest in small forks. A very fine one measures, 

 outwardly, one and three-fourth inches broad by one and a half 



