Reproductive Activities of Rosy Finches, with Special Reference to Montana

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THE Gray-crowned Rosy Finch (Leucosticte tephrocotis) is found throughout the higher mountains of western North America and is one of the few species of birds which breed in the alpine (Arctic) zone. Few detailed nesting records of the species exist because most of this high, rugged country is inaccessible by road and all of it has a short summer season. However, Logan Pass in Glacier National Park, Montana, offers a unique opportunity to reach this alpine habitat via a paved road. The Park's one million acres are characterized by large U-shaped glaciated valleys and high aretes and horns. Peaks run from 8,000 feet to 10,500 feet in elevation. Many glaciers and permanent snow fields occupy cirques in the higher portions of the mountains. Logan Pass was the focal point of a four-year study (1958-1961) of the breeding activities of the race L. t. tephrocotis, while I was employed as a ranger-naturalist. Unless otherwise indicated, all comments refer to this race and this area. Although this race of rosy finch inhabits an extensive range extending from the Brooks Range of northern Alaska southward through the higher mountains to northwestern Montana (A.O.U. Checklist, fifth edit., pp. 564-565, 1957), only one nest has previously been reported in the literature (Macoun and Macoun, 1909: 466) and no detailed nesting observations have been published. The present observations supplement recent studies of L. atrata by French (1959b) and earlier studies of L. t. dawsoni by Twining (1938, 1940). References made to these authors throughout the paper refer to the respective forms indicated here unless otherwise stated. The A.O.U. Check-list (1957) separates the genus Leucosticte into three species: L. atrata (Black Rosy Finch), L. australis (Brown-capped Rosy Finch), and L. tephrocotis. The last includes six races: L. t. umbrina, griseanucha, littoralis, tephrocotis, wallowa, and dawsoni. French (1959a: 21) considers all American forms of Leucosticte to be included in the species Leucosticte tephrocotis and Vaurie (1959: 623) further states that the American forms are conspecific with the Asian L. arctoa. The A.O.U. nomenclature has been adopted here since the taxonomic arrangement may not be fully resolved.