Context. Reproduction is a critical component of fitness, and understanding factors that influence temporal and spatial dynamics in reproductive output is important for effective management and conservation. Although several indices of reproductive output for wide-ranging species, such as migratory birds, exist, there has been no theoretical justification for their estimators or associated measures of variance.Aims. The aims of our research were to develop statistical justification for an estimator of reproduction and associated variances on the basis of an existing national wing-collection survey and banding data, and to demonstrate the applicability of this estimator to a migratory game bird.Methods. We used a Bayesian hierarchical modelling approach to integrate wing-collection data, which provides information on population age ratios, and band-recovery data, which provides information on recovery probabilities of various age classes, for American woodcock (Scolopax minor) to estimate productivity and associated measures of variance. We present two models of relative vulnerability between age classes: one model assumed that adult recovery probabilities were higher, but that annual fluctuations were synchronous between the two age classes (i.e. an additive effect of age and year). The second model assumed that adults, on average, had higher recovery probabilities than did juveniles and that annual fluctuations were asynchronous through time (i.e. an interaction between age and year).Key results. Fitting our models within a hierarchical Bayesian framework efficiently incorporates the two data types into a single estimator and derives appropriate variances for the productivity estimator. Further, use of Bayesian methods enabled us to derive credible intervals that avoid the reliance on asymptotic assumptions. When applied to American woodcock data, the additive model resulted in biologically realistic and more precise age-ratio estimates each year and is adequate when the relative vulnerability to sampling only slightly varies or does not vary among components of a population (e.g. age, sex class) among years. Therefore, we recommend using woodcock indices from our analysis based on this model. Conclusions.We provide a flexible modelling framework for estimating productivity and associated variances that can incorporate ecological covariates to explore various factors that could drive annual dynamics in productivity. Applying our model to the American woodcock data indicated that assumptions about the variability in relative recovery probabilities could greatly influence the precision of our productivity estimator. Therefore, researchers should carefully consider the assumption of temporally variable relative recovery probabilities (i.e. ratio of juvenile to adults' recovery probability) for different age classes when applying this estimator.Implications. Several national and international management strategies for migratory game birds in North America rely on measures of productivity from harvest survey parts co...

Black vultures (Coragyps atratus) have been increasing in density and expanding their range in the eastern United States since at least the 1960s. In many areas, their densities have increased to the level where they are causing damage to property and livestock and the number of requests for allowable take permits has increased throughout these areas. The United States Fish and Wildlife Service (USFWS) requires updated information to help inform the number of take permits that could reduce conflicts while meeting obligations under the Migratory Bird Treaty Act. We expanded analyses used to estimate allowable take in Virginia to cover the range of black vultures in the eastern United States. We used the prescribed take level approach, which integrates demographic rates, population size estimates, and management objectives into an estimate of allowable take. We provide estimates of allowable take at 4 different scales: individual states, Bird Conservation Regions, USFWS administrative regions, and flyways. Our updated population time series provides evidence of rapidly increasing black vulture populations in many regions of the eastern United States, with an overall population estimate of approximately 4.26 million in 2015 in the Atlantic and Mississippi Flyways. Estimated allowable take ranged from a few hundred individuals per year in states at the northern end of the species range to approximately 287,000/year over the entire eastern United States. The USFWS has no legal mandate regarding the spatial scale at which take should be managed and we found little biological evidence of subpopulation structure for black vultures in the eastern United States. We suggest that allowable take for the species be implemented at a scale that meets stakeholder objectives (e.g., reducing conflict, and ensuring that black vultures are not extirpated from local areas) and is efficient for administrative and monitoring purposes. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Unlike most prairie-nesting ducks, the North American population of northern pintails (Anas acuta) has shown limited response to improved wetland conditions on the U.S. and Canadian prairies during the mid to late 1990s. Because adult female survival is a key parameter affecting waterfowl population dynamics, and a large fraction of annual mortality for some dabbling ducks occurs during the nesting season, we used radiotelemetry to estimate nesting season survival and cause-specific mortality of adult female northern pintails that were monitored during an induced renesting study. We conducted our research in a predominantly agricultural landscape in southern Saskatchewan during 1998-2000, an area that is typical of much of the pintail's prairie breeding range. The survival rate of 140 females for a 75-day interval (30 Apr-14 Jul) during the nesting season was 0.806 ± 0.046. Survival did not vary among years or between ages (second-year, after second-year), nor was it related to female body condition (body mass adjusted for structural size, date, and year of capture). We documented 15 mortalities and found that the 75-day mortality rate due to raptors (0.141 ± 0.040) was greater than that due to red fox (Vulpes vulpes; 0.011 ± 0.011), collisions with power lines (0.011 ± 0.011), or unknown factors (0.039 ± 0.027). Our results differ from prior research that indicated red fox was a major predator of female pintails during the nesting season. Raptors were the primary mortality agent for female pintails, perhaps because of limited exposure during incubation in our study, or the use of open habitats by pintails in southern Saskatchewan. Management programs that provide nesting or wetland habitats with overhead concealment, or that reduce perch sites for raptors in areas with high pintail densities, may decrease the risk of avian predation on female pintails. JOURNAL OF WILDLIFE MANAGEMENT 69(2):574-581; 2005

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