Plasticity for breeding dates may influence population vulnerability to climate change via phenological mismatch between an organism’s life cycle requirements and resource availability in occupied environments. Some life history traits may constrain plasticity, however there have been remarkably few comparisons of how closely-related species, differing in key traits, respond to common phenology gradients. We compared population- and individual-level plasticity in clutch initiation dates (CID) in response to spring temperature among five duck species with early- to late-season nesting life histories. Plasticity was strongest in females of the earliest breeding species (common goldeneye [Bucephala clangula], mallard [Anas platyrhynchos], and gadwall [Mareca strepera]), whereas late-nesting lesser scaup (Aythya affinis) and white-winged scoter (Melanitta fusca deglandi) did not respond. These results contrast with previous work in other bird families that suggested late-breeders are generally more flexible. Nevertheless, late-breeding species exhibited annual variation in mean CID, suggesting response to other environmental factors unrelated to spring temperature. Goldeneye and gadwall females varied in their strength of individual plasticity (‘individual × environment’ interactions) and goldeneye and scoter females showed evidence of interannual repeatability of CID. Fitness consequences of CID plasticity in response to spring phenology, including trophic mechanisms and population consequences, warrant investigation.

Avian Conservation and Ecology 14(2): 8 http://www.ace-eco.org/vol14/iss2/art8/ à différents stades de leur cycle de vie annuel. Ces facteurs sont souvent structurés de manière hiérarchique et peuvent influencer les populations aux niveaux local, régional ou continental. Certains des défis associés à la délimitation des populations et l'identification des facteurs qui influencent les populations peuvent être traités à l'aide de la multitude de méthodes d'échantillonnage et d'analyse disponibles pour examiner l'évolution de la population au fil du temps. Le choix de méthodes d'analyse appropriées dépend des objectifs de l'étude et de la nature des données, par exemple des populations uniques ou multiples, les enquêtes répétées ou basées sur des comptes ou les taux démographiques. Les progrès récents des modèles de populations hiérarchiques et intégrés ont fait de certaines de ces approches analytiques les orientations les plus prometteuses pour le développement des méthodes futures. Toutefois, ces outils requièrent d'importants jeux de données ; or, l'acquisition de données suffisantes sur les populations aviaires et de variables d'explication potentielles est complexe dans la forêt boréale. Si l'on veut surmonter les défis actuels à la surveillance des oiseaux dans la forêt boréale, il convient de consacrer des efforts importants à l'intégration et à la mise à disposition des données existantes. Le renforcement des efforts d'enquête portant sur des espèces multiples jouera également un rôle important. La mise en oeuvre de programmes d'échantillonnage équilibrés avec un modèle à panel rotatif pourrait équilibrer les compromis entre réplication spatiale ou temporelle moyennant un coût raisonnable. L'amélioration de l'accès aux co-variables environnementales explicites sur le plan spatial et temporel permettrait en outre d'élaborer des modèles de population mécaniques qui amélioreront notre compréhension de la dynamique des populations d'oiseaux migrateurs. Enfin, compte tenu du fait qu'il faut parfois de nombreuses décennies pour que les programmes de surveillance à long terme produisent des tendances fiables en matière de populations et que les priorités des organisations évoluent au fil du temps, nous pensons que des efforts collaboratifs contribueront à assurer la pérennité des nouveaux programmes de surveillance.

Understanding habitat associations of breeding mallards (Anas platyrhynchos) and Canada geese (Branta canadensis maxima) in the eastern US and Canada is important for conservation planning, yet studies at spatial scales useful to conservation planners have mostly occurred in the midcontinent prairie pothole region (PPR). Our broad objective was to determine whether breeding pairs were associated with similar habitat types in an eastern ecozone, the mixed woodland plain of southern Ontario, Canada, as they are in the PPR, despite substantial differences in relative habitat availability and land use practices. We used helicopter surveys and remote sensing to investigate habitat associations at landscape (25 km2) and local (500 m wetland buffer [79 ha]) scales during the 2008 and 2009 breeding seasons. At both spatial scales, mallard indicated breeding pairs (IBP) were positively associated with the abundance or area of temporary open water and emergent (seasonal or semipermanent) wetland types, similar to the PPR. However, against expectations, we did not detect an effect of grassland area. Canada goose IBP were most strongly associated with total wetland abundance, and not specifically with emergent and permanent open‐water wetlands as expected. At the local scale, goose IBP presence was positively associated with riverine wetland area. Unlike the PPR, our study area contained a high proportion of forested and riverine wetlands; however, with the exception of the riverine wetland–Canada goose association noted above, we did not detect a disproportionate influence of these wetland types on mallards or geese. © 2015 The Wildlife Society.

Monitoring annual change and long‐term trends in population structure and abundance of white‐tailed deer (Odocoileus virginianus) is an important but challenging component of their management. Many monitoring programs consist of count‐based indices of relative abundance along with a variety of population structure information. Analyzed separately these data can be difficult to interpret because of observation error in the data collection process, missing data, and the lack of an explicit biological model to connect the data streams while accounting for their relative imprecision. We used a Bayesian age‐structured integrated population model to integrate data from a fall spotlight survey that produced a count‐based index of relative abundance and a volunteer staff and citizen classification survey that generated a fall recruitment index. Both surveys took place from 2003–2018 in the parkland ecoregion of southeast Saskatchewan, Canada. Our approach modeled demographic processes for age‐specific (0.5‐, 1.5‐, ≥2.5‐year‐old classes) populations and was fit to count and recruitment data via models that allowed for error in the respective observation processes. The Bayesian framework accommodated missing data and allowed aggregation of transects to act as samples from the larger management unit population. The approach provides managers with continuous time series of estimated relative abundance, recruitment rates, and apparent survival rates with full propagation of uncertainty and sharing of information among transects. We used this model to demonstrate winter severity effects on recruitment rates via an interaction between winter snow depth and minimum temperatures. In years with colder than average temperatures and above average snow depth, recruitment was depressed, whereas the negative effect of snow depth reversed in years with above average temperatures. This and other covariate information can be incorporated into the model to test relationships and provide predictions of future population change prior to setting of hunting seasons. Likewise, post hoc analysis of model output allows other hypothesis tests, such as determining the statistical support for whether population status has crossed a management trigger threshold. © 2020 The Wildlife Society.