Life History of the Black Rosy Finch

TI•E Black •osy Finch, Leucosticte tephrocotis atrata, is a member of a genus of bir• restricted in their breeding range to the high altitudes of the mountai• of western North America and Asia.No previous intensive study has been made of this fo•.•he North American rosy finches are usually considered three species (L.tephrocotis with several subs•cies, L. atrata, and L. australis), because of their somewhat different coloration and their presumed allopa•ic distribution (A.O.U.Check-list, I•57: 5•4-5•).•he breeding range of the Black •osy Fin•, interpo•d between those of L.t. tephrocotis and L.t. australis, includes the mountains of Idaho, Montana, Ut•, Wyoming and northeastern Nevada.During these studies, at least two regions of inter•a•tion were found in the mountains of Idaho and Montana where populational interchange, with resulting mixing of •acters of L.t. tephrocotis and L.t. atrata, occurs.Detailed distributional data have been presented in a separate pa•r (Fren•, 1959), and the conclusion has been reached that all the American rosy finches should be treated as races of one species, L. tephrocotis.The Bla• Rosy Fin• is the only American Leucosticte showing strong sexual dimorphism.The m•e is sooty blab, with a pink wash on the lateral p•ts o[ the body, especially interne on the wing and tail coverts, and with a light •ay •escent extending from eye to eye over the back o[ the •own.The female is mu• duller, has the back and wings more brownish, the abdomen •ayish, the head markings indistinct, and the pink wash paler, sometimes bu• or whitish.During the breeding season the Black Rosy Finch is found only above timberline.This may be upwards of 9,000 feet in some mountain ranges, while in others birds breed o•y above 11,000 feet elevation.In the mountains inhabited there seems to be no upper altitudinal limit to the range.In winter Black Rosy Fin•es descend to lower elevations, being found in flocks from 7,000 feet down to at least 4,000 feet in valleys of southern Wyoming, western Colorado, Utah, Nevada, and adjacent parts of California, and New Mexico.STUDY AR• AND ME•ODS Three summers, 1951, 1952, and 1953, were spent making daily observations o[ Black Rosy Finches in their breeding habitat in the Teton and Abs•oka mountains of Wyoming and the Uinta Mountains of Utah.In addition, at least eight other mountain ranges were visited to observe and collect specimens.Winter observations and � EI 1 959 THE AUK, VOL.76 PLATE 5 Br•ding habitat of ibc Black Kosy Finch (Leucosticte t. atra•a).(•bove) Condition above 10,000 f•t elevation in tbc Wasatch Mountains of Utah in April, 1953, at tbc time of arrival of the birds on the br•ding grounds.(Below) Cli• u•lized for nesting by the birds.Bald Mountain, Uinta Mountains, Utah, .June, 1953.THE AUK, VOL.76 PLATE 5 Br•ding habitat of ibc Black Kosy Finch (Leucosticte t. atra•a).(•bove) Condition above 10,000 f•t elevation in tbc Wasatch Mountains of Utah in April, 1953, at tbc time of arrival of the birds on the br•ding grounds.(Below) Cli• u•lized for nesting by the birds.Bald Mountain, Uinta Mountains, Utah, .June, 1953.THE AUK, VOL.76 PLATE 5 Br•ding habitat of ibc Black Kosy Finch (Leucosticte t. atra•a).(•bove) Condition above 10,000 f•t elevation in tbc Wasatch Mountains of Utah in April, 1953, at tbc time of arrival of the birds on the br•ding grounds.(Below) Cli• u•lized for nesting by the birds.Bald Mountain, Uinta Mountains, Utah, .June, 1953.