Foraging Habitats and Foraging Techniques of Five Wintering Anatidae Waterfowl in Light of Genetic Distances

AbstractThe diversity of foraging behaviour in waterfowl species is often estimated to mostly be the result of adaptations to different foraging habitats and diets. Understanding of adaptive radiation within a rapidly multiplying lineage can be used to detect behavioural patterns and can also be useful in identifying the underlying factors in the emergence of divergence of foraging behaviour within a lineage. This paper recorded the similarities and dissimilarities in foraging behaviour of five nonbreeding Anatidae waterfowl in different foraging habitats. Genetic distances between these waterfowl might have influenced the foraging behaviour of these species. Phylogenetic tree of the birds based on mitochondrial DNA supported the observation. Pairwise post hoc analyses of the species highlighted significant differences between foraging techniques employed by these Anatidae birds. Canonical Correspondence Analysis clearly demarcated the foraging preferences between three prominent clusters of waterfowl species being studied. Generalist nature of foraging behaviour was recorded in Lesser Whistling Duck, which branched apart early in the evolution. Northern Pintail, Red-crested Pochard, Common Pochard, and Tufted Duck showed specialized foraging behaviour such as predominantly upending and diving. Significant Pearson correlation coefficient (p < 0.01) between genetic distance and time allocated for diving was 0.899, and the corresponding coefficient for upending was 0.876. Red-crested Pochard, which is considered to be a link between dabbling ducks (Anatinae) and pochards (Aythyinae), showed interesting foraging behaviour to attest their phylogenetic position between divers and dabblers depending on the foraging habitats. Red-crested Pochard used beak-dip more frequently like Northern Pintail. Gene-mediated physical and physiological constraints might have led to the behavioural dominance on a particular foraging technique and resource partitioning in a given habitat, which has supported the stable coexistence of several waterfowl in a wetland.