Reproductive ecology of the mourning dove: large-scale patterns in recruitment, breeding endocrinology, and developmental plasticity

Abstract

The national strategic management plan for the mourning dove calls for the implementation of an operational monitoring program of recruitment rates that is national in scale. Age ratios estimates, i.e. juveniles per adult, generated from harvest wing collections are a potentially efficient method for large-scale monitoring of recruitment for the species. Generating unbiased estimates of recruitment from harvest age ratios requires calibration of estimates to account for wings of unknown-aged birds in the sample and for differential vulnerability of the age classes to harvest. We present results from the first national-scale effort to estimate dove age ratios while addressing the need to develop a simple, efficient, and generalizable methodology for calibrating estimates. Our method predicts age classes of unknown-age wings based on backward projection of molt distributions from fall harvest collections to late-summer banding. Estimated parameters are 1) the proportion of late molt individuals that belong to each age class and 2) molt rates of juvenile and adult birds. Monte Carlo simulations demonstrate that the estimator is minimally biased. We estimated model parameters using 96,811 wings collected and 42,189 birds banded from 68 collection blocks in 22 states during the 2005-2007 hunting seasons. Estimates were also used to derive a correction factor based on latitude and longitude of samples that can be applied to future surveys. In addition, we estimated differential vulnerability of the age classes to harvest using data from banded birds and applied this to harvest age ratios to estimate population age ratios. Using harvest age ratios from an independent sample of 41,084 wings collected from random hunters in 2007 and 2008, we found that the average uncorrected