Mortality Estimates of an Adult Band-Tailed Pigeon Population in Orgeon

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In the period 1952-65, 3,140 band-tailed pigeons (Columba fasciata) were banded at Nehalem, Oregon, during each May and June when the birds were in prebreeding flocks of adults. These banding efforts averaged 56 new captures per trap-day over the 14-year period. The average annual mortality rate based on 262 recoveries was 28.7 percent. When return data were used to calculate mortality, 687 records indicated a rate of 29.1 percent. Productivity of this population, assuming that the population has remained relatively stable in size, was estimated to be about one young per pair when a 40 percent immature mortality rate was assumed. The purpose of this paper is to present estimates of adult mortality rates and deductions on the probable productivity of a population of band-tailed pigeons banded at Nehalem, Oregon. The band-tailed pigeon is a migratory game bird of the western states and provinces of the United States, Canada, and Mexico. It is a species of low productivity. Various authors (Bent 1932, Neff 1947, Morse 1949, and Glover 1953) report one egg per clutch and only one brood per year as normal. However, MacGregor and Smith (1955) in a study in Monterey County, California, found evidence of multiple nesting. One marked pair fledged three broods in 1954. One egg per clutch was considered normal in all studies. For the purpose of this paper, a recovery is defined as a banded bird shot or found dead and reported. A direct recovery is a recovery that occurs in the year of banding or more specifically during the hunting season that immediately follows the banding period. A return is a recapture of a bird from our bandings that occurs at the trap site one or more years following the year of banding. We wish to acknowledge the editorial assistance and statistical advice of W. Scott Overton, Department of Statistics, Oregon State University.