Social and habitat correlates of immigrant recruitment of yearling female Mallards to breeding locations

Abstract

Conspecific avoidance and attraction hypotheses have been proposed to explain patterns of animal spacing behavior and have been frequently used to explain habitat selection by dispersers. In birds, tests of these hypotheses have been limited to fine spatial scales and have not considered dispersal distance. We used discriminant function analysis (DF) of feather d 34 S, dD, d 15 N and d 13 C values to identify yearling female Mallards (Anas platyrhynchos) that dispersed long distances ([400 km relative latitude) from natal areas to settle at 22 breeding locations in the Canadian parklands, 1993-2000; these sites varied in social (breeding pair density) and breeding habitat (wetland density and percent nest cover) conditions. DF indicated that the proportion of yearling female recruits estimated to be long-distance immigrants in these breeding populations averaged 12% across sites (range 0-38%). Yearling immigration rates were positively correlated with conspecific breeding pair density and negatively correlated with percent wetland habitat. Settling patterns by yearling immigrants were most consistent with the prediction of social attraction, but effects were statistically weak possibly because inter-regional movements were less variable annually due to relatively stable wetland conditions in the southern prairies during the period of study. Our results suggest immigrants arriving from distant natal sites used conspecific abundance as a positive cue of habitat quality when choosing the new breeding sites. Fitness consequences of these choices should be evaluated.

Density-dependent nest predation in waterfowl: the relative importance of nest density versus nest dispersion

“…ConspeciWc attraction has long been recognized as an important factor in avian habitat selection (Hilden 1965), and recent observational and experimental work has shown that conspeciWc attraction can convey useful information about habitat quality and breeding success Doligez et al 2004;Ward and Schlossberg 2004). Few waterfowl studies have explicitly studied conspeciWc attraction, but each has found that conspeciWc attraction can be a more important cue than habitat in nest site selection (Pöysä et al 1998;Coulton et al 2011).…”

Assessing breeding duck population trends relative to anthropogenic disturbances across the boreal plains of Canada, 1960–2007

“…Relationships between anthropogenic disturbances and breeding success may be different than those observed for breeding pair settling if different ecological processes influence female survival, nest success, and/or duckling survival. Furthermore, immigration of pairs from other regions could mask effects of reduced local breeding success (Coulton et al 2011), creating population sinks. Thus, a more thorough assessment of anthropogenic disturbances as foci for conservation action requires examination of both pair settling and their breeding success.…”

An experimental test of information use by wood ducks (Aix sponsa): external habitat cues, not social visual cues, influence initial nest site selection

“…Our results have management and conservation implications and offer some insight on the divergent trajectories that appear to characterize nest site selection studies by gamebird vs. non-gamebird bird ecologists. A large number of studies have now recognized the importance of both social and personal information use in nest site selection by birds (Ahlering et al 2010;Ahlering and Faaborg 2006;Betts et al 2008;Campobello and Sealy 2011;Chalfoun and Schmidt 2012;Coulton et al 2011;Nocera and Betts 2010;Szymkowiak 2013;Ward et al 2010). However, studies of waterfowl have focused more on habitat characteristics affecting nesting behaviors, while studies of passerines tend to focus more on the importance of social information (see also Eichholz and Elmberg 2014;O'Neil et al 2014).…”