| Description |
Field studies were conducted during 1971 and 1972 to determine the composition and density of the avifauna of Red Butte Canyon in the Wasatch mountains east of Salt Lake City, Utah Red Butter Canyon represents an area of nearly unaltered conditions, having been closed to the public since the turn of the century. The canyon has recovered from grazing and rock quarrying activities in pioneer times which started in 1848. A botanical study in 1935 comparing two similar adjacent canyons found that the vegetation of Red Butte Canyon was twice as dense as that of Emigration Canyon. The present study pertained to an analysis of the composition, density, and ecological distribution of the birds. Four habitats were selected for detailed study: 1. oak community, 2. maple community, 3. mixed community of boxelder, birch, alder, maple and, 4. cattail marsh. The ecological distribution, relative frequency of observation and densities of the birds of each of these habitats were determined. The results allow comparison of the birds of one habitat type to another in the canyon as well as with similar habitats found elsewhere. The size of the sample plot for each habitat was five acres except the cattail marsh which was only one acre. Repeated strip censuses were made for each habitat. Seventy visits were made to the study sites ranging throughout the twelve months of each of the tow years. In expressing the densities of populations three methods were used: 1. total birds observed, 2. birds per acre, and 3. frequency of percentage. Comparison of habitats was made where individual species occurred in more than one study area so as to determine preferences for particular habitat types. Results of the study were as follows; 106 birds were found to occur in the canyon of which 36 are permanent residents, 42 are summer residents, (thus 78 breeders) 25 are migrants, and 3 winter residents, As regards the breeding forms, densities and numbers of kinds of birds were greatest in the mixed community. The Lazuli Bunting was the commonest species inhabiting the oak community. In the mixed and maple communities the Black-capped Chickadee was the most abundant bird. Species found in the marsh community generally had a higher density per unit area than those of the other habitat types. Seasonal changes in the elevation of occurrence of the permanent residents varied markedly during the winter months, many showing altitudinal migration. graphs present the seasonal occurrence, ecological distribution and relative abundance of the 106 birds. Species accounts furture summarize the data acquired. |
