286 
REPORT OF THE CHIEF OF ENGINEERS. 
It is a curious fact in the history of this species that, in the fall, when the seas > 
love, which is supposed to directly inspire the music of birds, has long since passe* , 
and most other songsters are either entirely silent or their songs are limiteb. o 
first rude practicings of the young males, the Townsend’s flycatcher should now 
not at rare intervals, hut as a regular habit—give utterance to snatches ot meiot y 
that, though but a fraction of its splendid powers, may yet challenge the utrnos 
efforts at emulation of most other species. And I am by no means sure that such mu¬ 
sical rivalry as takes place at this time among the males does not owe its origin, in 
part at least, to the fading embers of a passion not yet fully spent. At all events, x 
have often seen, at this season, two males in eager pursuit of a companion appaien ly 
some coy female—that led them an eager chase for five or ten minutes at a time, in a 
way that could suggest only the ardor of the mating season. The males eDgaged in 
such a chase are always full of song, which pours out as brilliant snatches and liag- 
ments of their fuller, more perfect symphonies of spring. 
Oroscoptes Baird. 
0. montan'us (Towns.). .Sage-Thrasher. 
Nowhere in the wide region inhabited by this thrush is it more abundant than on 
the sage-covered hills and plains of Western Nevada, just at the base of the mount¬ 
ains which shut off the western extension of the species. 
In a climate like that of Nevada, where the transition period from spring to sum¬ 
mer is never very well marked, and summer is at hand almost as soon as the snow dis¬ 
appears, there are always to be observed great irregularities in the time of nesting of 
the birds. This is as true of the smaller as of the larger species. Thus, taking the 
present bird as an example, the 20th of May appears to be just about the height of its 
breeding season. Although at this time not a few pairs were feeding full broods, 
yet the majority of the nests contained fresh eggs, while some dilatory couples had 
but just brought their homes to completion. There was thus to be noted a difference 
of fully six weeks between the earliest and latest periods of deposition of the first 
clutches of eggs. 
As the eye passes over the sage plains of the far West it finds a broad, slightly un- 
dulatory expanse, covered everywhere with the characteristic sage-brush and present¬ 
ing to the sight no breaks in its apparently smooth surface. In reality, however, the 
plains are very far from being level, and it needs but a short walk in any direction to 
reveal the presence of unsuspected little valleys and ravines, their boundaries traced 
on either side by more or less abrupt rocky ridges.- It is along the crests and sides of 
just such ridges that the sage-thrasher is most at home, and in the vernal season, at 
intervals of every few hundred yards, the males may be heard pouring out at all times 
of day their delightfully melodious strains. In the presence of its humble associates, 
the Bell’s finch and Brewer’s sparrow, which alone share its desolate surroundings, our 
thrush finds no rivalry to stimulate its efforts; but, unmindful of this, it sings on, finding, 
perhaps, its reward in the satisfaction born of its owu powers or the delight its strains 
carry to the heart of its silent brooding mate. Its song, though not possessed of great 
variety, is noteworthy for its sweetuess and expression. 
The nests, of which I have examined very many, vary but little either in composi¬ 
tion or situation. Solidity and bulkiness sum up their chief characteristics. The foun¬ 
dation is of sticks and twigs, the thorny character of which enables them to be firmly 
interlocked, so as to form a strong support capable of resisting all ordinary accidents, and 
even to defy wind and weather for many successive seasons. I do not think, however, 
they are ever utilized a second time. The inner or nest proper is made of rootlets, with 
perhaps a few horse-hairs, which are woven into a circular depressed cup. 
Numerous sets of eggs compared together show but little variation, aud this chiefly 
in the amount and method of distribution of the spotting rather than in the colors 
themselves. 
SAXICOLID^E—Stone Chats. 
Sialia Swainson. 
S. mexieana Sw. Mexican Bluebird; Chestnut-back Bluebird. 
Thisisthe common bluebird of the region. During the summer it inhabits not only the 
low valleys, but, to even a greater extent, the mountains, being there found in the dense 
pine timber up to about 6,U00 feet. As is the usual custom of the Eastern species, the 
present bird, as indeed also the Arctic, raises two broods during the summer, and the 
season is far advanced ere family duties cease. 
S. arctica Sw. Arctic Bluebird. 
The habitat of the preseutbird is, in general, more northern than that of the preceding. 
Nevertheless, the two species are not infrequently marked in local lists as inhabiting 
