SIERRA NEVADA ROSY FINCH. Leucosticte tephrocotis dawsoni Grinnell

Field characters.—Larger than Junco; size of White-crowned Sparrow. Color chiefly deep chestnut brown, with rosy red edges or tippings to feathers on rump, tail, and base of wing; forehead black, joined behind by a broad gray patch which extends down to level of eye. Female lighter than male in tones of color; body plumage of young more grayish. (See pl. 1.) Forages in scattered flocks on open ground, usually above timber line. Flight and manner much as in Siskins, though size considerably greater. Voice: Loud, rather hoarse chirps, few together, rarely anything like a chorus. No song of any sort heard by us.

Occurrence.—Resident in Alpine-Arctic Zone, descending at times into Hudsonian. Most often seen in summer on open ground around edges of snow banks above the 10,500-foot contour. Westernmost stations, Mount Hoffmann and Mount Clark; easternmost, Warren Mountain. In pairs at nesting time; flocking at other seasons.

The Sierra Nevada Rosy Finch, or Leucosticte, is the most typically alpine of all Californian birds. The mountaineer does not meet with it until he reaches the main Sierran crest or at least the loftiest of the outstanding spurs. Constantly surrounded by extremes of cold and bleakness, and by vast declivities, a combination most forbidding to us, the rosy finch excites our astonishiment at his choice of habitat if for nothing else. He is one of the innumerable sparrow tribe, not so very different in many features from the finches of the lower altitudes. It seems that he has been crowded out of the better parts of the land by his more successful relatives, until now he has left for himself only the last and least hospitable strip of territory. He certainly has no competition there; he is usually the sole avian tenant of his domain, save for, in summer, some vagrant rock wren or junco from below. No one is contesting with him for possession. The following typical experience, recorded on the spot by the senior author, gives an idea of some of the peculiarities of the bird and of its habitation.

Fig. 52. Bills of (a) Cassin Purple Finch, (b) California Evening Grosbeak, and (c) Sierra Nevada Rosy Finch, from above. Natural size. The Rosy Finch remains in the cold high country throughout the winter and is well provided with a "snow-mask" over the nostrils.

On treeless ridge at about 11,000 feet, above Vogelsang Lake, afternoon of August 31: sharp west wind; black clouds piling along; reverberating peals of thunder at intervals; dashes of rain now and then, driving over the ridge. A dozen or more rosy finches are in sight, forming a loose flock which flies bravely from the lee side up into the teeth of the wind, only to be overwhelmed and swept back into space above the great glacial basin lying below. Presently they rally and come up again, this time tacking diagonally; then they dash by, across the wind, skimming the ledges in a headlong course toward a distant snow bank, to be quickly lost to the eye. All the while quaint chirps apprise the observer of the presence of the birds somewhere in the vicinity, although direction becomes hopelessly mixed amid the eddying gusts. No matter how far adrift the birds go in their wild flights, the snow field seems to hold them magnetized, for back they always swing. The flights themselves seem of no use in the economy of existence: Can they be expressions of jubilance resulting from excess of vigor? One can imagine the rosy finches similarly disporting themselves in midwinter about the selfsame ridges. The scanty vegetation now going to seed is then uncovered periodically by the winter gales, so that their accustomed fare is continually available at one place or another.

Our findings in the Yosemite Park and elsewhere along the Sierras tend to show that the food of the Leucosticte even in summer consists predominantly of seeds, with possibly buds, of the dwarfed plants which grow at and above timber line. This is contrary to the testimony of several observers, who, upon seeing the birds hopping about the edges of snow banks where numbers of benumbed insects are often seen stranded on the snow, conclude that the birds are engaged solely in gathering these 'cold-storage bugs.' To most members of our field party who watched them, the birds on or around snow banks appeared to be shucking out the seeds of the previous year's crop, which the melting snow continually exposed. Such a food supply carries over until the new crop is ripe. Some of the seeds are sifted through the snow as it is swept into drifts by the autumn winds; others are buried while still in the head, to be revealed only with the receding of the snowfields as summer advances. One bird watched by the junior author at the head of Lyell Cañon, July 17, was getting seeds out of dry grass-heads at the rate of sixty a minute.

On the other hand, two of our party reported undoubted instances of animal food being taken. Mr. Camp noted numbers of Leucostictes about the top of Conness Mountain above the 12,000-foot level, July 8, 1915. Here they were, as usual hopping about the snow banks, and one bird was plainly seen to pick up the cold-storage insects "continuously for two minutes at the rate of one insect per second." The insects seen in the snow were mostly small flies. Butterflies, moths, beetles, and squash-bugs were also represented. The birds were in companies of six or less, and would usually allow of an approach to within fifty feet. Again, on Dana Meadows, July 6, 1916, Mr. Dixon watched two adult rosy finches "pulling worms out of the turf." The birds were approached to within a distance of twenty feet and even then they kept at their business with extraordinary indifference.

The present contention as to the prevalently vegetable character of the food of the Sierra Nevada Rosy Finch is upheld by the contents of the crops of several of the birds taken for specimens in August, 1911, in the Mount Whitney region. These crops, ten in number, were subjected to careful examination and their contents found to consist 91 per cent of small seeds, and 9 per cent only of insects. The dilated gullet of a bob-tailed young one taken August 22, 1915, on Mount Clark contained a gruel-like mixture of shelled seeds (35 per cent) and insects (65 per cent),²⁴ evidently just fed to it by one of the parents. This last bit of evidence is most important; for in certain seed-eating birds, which adhere closely to a vegetable diet most of the year, the young are fed with a greater or less proportion of insects. The rosy finch seems to belong, along with chipping sparrows and juncos, to this category of fringillids, rather than with the strict vegetarians, like the linnets and goldfinches, to which structurally it is thought to be more nearly related.

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²⁴Stomach examinations made for us by the United States Biological Survey, through Dr. E. W. Nelson, Chief.

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We were not fortunate in finding any nest of the Sierra Nevada Rosy Finch in the Yosemite region. We have considerately left this accomplishment for someone with marked cliff-climbing predilections, together with unlimited patience and tireless powers of observation. An essential element in the search for a Leucosticte's nest would be time, but there might be an element of luck, too. We would suggest, first, the watching of a pair of birds to determine the focus of their interests; then the searching of the crevices of the rock chute or fractured brink of fluted cirque about which their fixed headquarters are almost sure to be found.

The nearest to finding a nest that any of us came, knowingly, was on the side of Mount Clark, August 22, when a half-grown young rosy finch, yet unable to fly, was traced by its hoarse chirp or chirrup to its hiding place in a rock crevice close to a snow cornice on the verge of a thousand-foot declivity facing toward the northwest. The nest must have been close by, though possibly altogether out of reach deep down in some one of the many clefts. This instance would indicate a late date of egg laying, probably about August 1. On the other hand, a female bird collected at 10,500 feet on Mount Hoffmann, June 30, contained a full-sized egg and showed evidences of having already deposited other eggs.

Young-of-the-year, fully feathered and flying about in restless flocks, were first observed August 29, at Vogelsang Pass. On September 26, flocks were seen along the ridge at the extreme head of Warren Fork of Leevining Creek, 10,500 to 11,000 feet. Not far away was found an adult male all alone on a rocky slope among lodgepole pines at only 10,000 feet altitude. He proved to be undergoing the fall molt, being extremely ragged in appearance, and doubtless unable to keep up readily with the flock of full-feathered young-of-the-year. As with certain other members of the finch family which are of flocking habit most of the year, the adults at molting time in the fall (there being no spring molt in this species) sequester themselves during the period of impairment preceding the acquisition of a complete new garb.

While our party was on the summit of Mount Lyell, 13,090 feet, July 18, a pair of rosy finches was foraging about among the rocks apparently picking up crumbs left from luncheons. On July 8, Leucostictes were seen about Young Lake (10,000 feet) and on August 21 a small company was seen on Mount Florence at 11,500 feet. One lone Leucosticte was seen at the Soda Spring, Tuolumne Meadows, only 8600 feet altitude, on the the evening of July 27, 1915, this being the lowest station of observation.