Trochilus alexandri.
It is exceedingly difficult to distinguish the female of this species from that of T. colubris. The size is rather larger, and the tail rounded, without any distinct emargination; the middle feathers being .15 of an inch longer than the lateral ones, instead of actually shorter. The color is much the same. The primaries are also much broader in the present species.
In both species the outer tail-feathers, though broader than in the male, are quite acutely pointed on the terminal third, one side or the other of which is slightly concave, instead of being linear to near the end, and rounded without any concavity, as in Selasphorus and Calypte.
Habits. This Humming-Bird, originally described as a Mexican species, is found from the highlands of that republic northward, not only to the southern borders of the western United States, but as far north as the 58th parallel. It was first discovered on the table-lands of Mexico, east of the city, by Signor Floresi, a distinguished naturalist, who devoted himself to the study of the Trochilidæ of Mexico, but was first added to the fauna of North America by Dr. Heermann, who detected it, and obtained several specimens, within the burying-ground of Sacramento City, Cal. There several pairs remained during the period of incubation, and reared their young, finding both food and shelter among the flowering plants of that cemetery. He found several of their nests which were essentially similar to the T. colubris.
Dr. Cooper met with this species along the Mohave River. He saw the first on the 3d of June. He also found one of their nests built in a dark willow-thicket in the fork of a tree, eight feet from the ground. Those afterwards found near Santa Barbara were all built near the end of hanging branches of the sycamore, constructed of white down from willow catkins, agglutinated by the bird’s saliva, and thus fastened to the branch on which it rested. These were built in the latter part of April, and early in May
contained two eggs, exactly resembling those of the T. colubris, and measuring .51 by .32 of an inch.
Afterwards Mr. W. W. Holden obtained a specimen in the Colorado Valley, March 20.
Mr. J. K. Lord, one of the English commissioners of the Northwestern Boundary Survey, met with this species near his camping-place on the western slope of the Rocky Mountains. This was near a lake, by the margin of which, with other trees, grew a number of the black birch. On these trees he found a sweet gummy sap exuding plentifully from splits in the bark, and on this sap hosts of insects, large and small, were regaling themselves. As the sap was very sticky, numbers of the smaller winged insects were trapped in it. Busily employed in picking off and devouring these captive insects were several very sombre-looking Humming-Birds, poising themselves over the flowers, and nipping off, as with delicate forceps, the imprisoned insects. Upon securing one of these birds, he ascertained that it belonged to this species. This was pretty satisfactory proof that they are insect-eaters. Not only on this occasion, but many times afterwards, Mr. Lord saw this bird pick the insects from the tree; and the stomachs of those he killed, on being opened, were filled with various kinds of winged insects. He found this bird lingering around lakes, pools, and swamps, where these birches grow. They generally build in the birch or alder, selecting the fork of a branch high up.
This species bears a very close resemblance in size, appearance, and markings, to the common eastern species, but is readily distinguishable by the difference in the color of the chin and the shape of the tail.
In the spring of 1851, on a trip to Sonora, Mexico, Dr. Heermann found these birds abundant in the arid country around Guaymas, where amid the scanty vegetation they had constructed their nests in the month of April. He also afterwards found them on Dry Creek and the Cosumnes River.