Life History of the Black Rosy Finch

Abstract

TIE 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 subscies, L. atrata, and L. australis), because of their somewhat different coloration and their presumed allopaic distribution (A.O.U.Check-list, I57: 54-5).he breeding range of the Black osy Fin, interpod 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 interation 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 par (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 me is sooty blab, with a pink wash on the lateral pts 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 oy above 11,000 feet elevation.In the mountains inhabited there seems to be no upper altitudinal limit to the range.In winter Black Rosy Fines 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 MEODS Three summers, 1951, 1952, and 1953, were spent making daily observations o[ Black Rosy Finches in their breeding habitat in the Teton and Absoka 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