Abstract

This paper deals with the life history and distribution of the Spurred Towhee (Pipilo erythropthalmus moutanus Swarth). Research was begun in April, 1955, and terminted in June, 1956. The preferred habitat of this bird is the mountain slopes, canyons. and streamsides covered with a shrubby type of vegetation, usually between 5,000 and 8,000 feet in elevation. Distribution of the Spurred Towhee is throughout the central Rocky Mountain region in the states of Wyoming, Utah, Colorado, Arizona, western half of New Mexico, and into northern Mexico. During the winter these birds are found concentrated in the lower valleys along the streams in some areas and in the lower reaches of the foothills in others. In April the flocks disband and the birds pair and establish territories. There are three distinct songs or sounds made by the towhee, and two of these have been analyzed in detail by first tape recording them and then analyzing them on a sona-graph. Few data were assembled concerning territorialism, but it is thought to exist. The five nests found during this study were all robbed of either their eggs or young. They were constructed upon the ground, with an inner lining of dry grass and an outer shell of sagebrush bark or cedar bark. The four nests found in Utah County were all under sagebrush. The usual clutch size is four. The female does all the incubating and the male sings vigorously during this time. The growth rate of the young is rapid. Only the male feeds the young, at least during the first six days of nest life, while the female does all the brooding. June 9 was the earliest juvenile towhee, were observed out of the nest. The principal source of food, according to another worker, is insects, except during winter months. The ideal habitat where populatlons were found to be highest was in areas where the vegetation was clumped with intermittent open spaces. Size, density, and kind of cover seemed to be the most important factors affecting populations, while slope and exposure had only an indirect effect.

Degree

College and Department

Life Sciences; Plant and Wildlife Sciences

Rights

http://lib.byu.edu/about/copyright/