BIRDS. 217 



■with scraps of deer-hair, feathers, and a little moss. A nest obtained by me near Saint Michaels 

 on the 1st of June is an extremely small, loose structure, formed by lining a small depression at 

 the base of a shrub in the midst of an alder-thicket with fine soft grass leaves. The material of 

 the nest is uniform throughout, and in this particular partly bears out Dr. Brewer's statement in 

 the History of North American Birds, which is: "The nests [of alioice] are also quite different in 

 their appearance and style of structure. The Hypnum mosses, so marked a feature in the nests of 

 T. swainsoni, as also in those of T. ustulatus, are wholly wanting in those of T. aliciw." This state- 

 ment is not confirmed, however, by the examination of other nests. A second example, obtained 

 at Saint Michaels on June 20, was composed mainly of these mosses mixed with a small amount of 

 coarse grass. This nest was placed upon the branching base of a small alder only a few inches from 

 the ground. The nest first mentioned measured 3J inches across the top by 2 inches deep, and the 

 eggs which it contained measure respectively .93. by .62, .90 by .64, and .93 by .68. These eggs 

 are blue, with a varying amount of reddish-brown specking, which is most abundant at the larger 

 end. In two specimens of this set the spots are thinly scattered over the shell, while in the other 

 two it is so distributed that over half the surface is concealed by it. Of the specimens in the 

 l^ational Museum collection some are scarcely marked at all, while in others the ground-color is 

 nearly hidden. The single egg found in the second nest measures .92 by .69. This nest measure^ 

 inches in depth by 4 inches in width, the central cavity being 2 inches deep. ^^ 



It may be remarked here that the nest just described is typical of the structure made by 

 swainsoni, according to Dr. Brewer, but, as every field-ornithologist is aware, any attempt to make 

 an exact science of zoology and of the study of the nests of birds must fail. Observation shows 

 that in building their nests birds are necessarily influenced by the surroundings and by the nature 

 of the material near their nesting-sites. The so-called instinct which has been supposed to lead 

 birds of one species to almost invariably select a certain kind of material and a certain position for 

 their nests has little foundation in fact. The nesting-range of the Gray-cheeked Thrush extends 

 throughout Alaska, as specimens have been obtained in all parts of the Territory, during the breed- 

 ing season, except, however, the islands of Bering Sea and the Aleutian chain. 



Fall specimens possess much more of the warm, buffy tint on the breast than spring birds, 

 although many of the latter have more or less, and in some specimens obtained by me from the 

 Yukon the buff is nearly as inj;ense and widely spread as upon typical examples of swainsoni. The 

 full-grown young of this species, obtained on the Lower Yukon, in August, 1877, has the dorsal sur- 

 face of a dull brownish-olive, nearly uniform, but with a lighter shade and a decided brownish wash 

 on the outer edges of the wing-feathers and on the tail, especially near the tip. The feathers on the 

 side of the head, embracing the eyes and extending back to the nape, including the scapulars and 

 intermediate feathers of the back, are each marked with a well-defined oval, lanceolate, or saggitate 

 central area, of a dingy whitish shade, which in some places becomes pale buffy-yellowish. The 

 feathers on the throat, neck, and breast are pale buffy- white, with black tips. These tips are larger 

 and more intense on the breast. They are centrally located and somewhat oval or arrow-shaped on 

 the throat, but on the breast they become a squarely-cut black edging to the feathers, which limit 

 the white by a nearly straight line. These tips pass to faint edgings of black on the white of the 

 middle of abdomen, and shade gradually into a brownish-olive on sides and flanks. The feathers on 

 the sides and rump are dingy yellowish-brown indistinctly barred with blackish. The middle of the 

 crown and rump are immaculate. The second specimen, obtained at Saint Michaels, August 25, is 

 in a little more advanced stage than the one just described, and has the pale buff shade across the 

 breast and sides of the neck of the second plumage. The lores are grayish-white, and the spots on 

 the breast are nearly as in the adult. The bill is dull horn-color, lighter at the base of the lower 

 mandible. Both of the specimens just described are merging into the second or adult plumage, but 

 the first is but very little changed, and has lost only the spots on the crown and rump and the white 

 tips on the wing-coverts. The second specimen, though a little older, still retains the faint wing, 

 bars formed by the light tips to the coverts. 



TuRDUS USTULATUS (Nutt.). Eusset-backed Thrush. 



At present this bird is known only from the coast of the southeastern portion of the Territory, 

 where Bischoff obtained several specimens, in the vicinity of Sitka. These specimens are the most 

 P. Miss. 156 28 



