Got Guts?: A Morphological Assessment of Migratory Waterfowl Digestive Anatomy


Phylogeny and diet influence digestive systems morphology. For example, many migratory species experience both hyperphagia and short-term fasting that affects digestive system function and morphology. For most wildlife, the extent to which digestive system morphology varies within a species is relatively unknown. Using migratory waterfowl as an exciting ecological model due to their complex digestive system morphology (e.g., gizzard, small and large intestine, paired ceca), our objective was to evaluate variation in digestive system morphology within and among different species of migratory waterfowl across diverse phylogenies. To achieve our objective, we sampled five species of waterfowl harvested by hunters in the Upper Peninsula of Michigan: ring-necked duck (Aythya collaris), mallard (Anas platyrhynchos), bufflehead (Bucephala albeola), wood duck (Aix sponsa), and green-winged teal (Anas carolinensis), and Canada goose (Branta canadensis). With permission from hunters, we extracted the complete gastrointestinal tract from harvested birds and systematically captured images of the entire gastrointestinal tract. We used ImageJ software to measure the gastrointestinal tract of each animal and ANOVA analysis to determine whether differences in digestive system morphologies were statistically significant. Our results indicate that variation among species was greatest when comparing the distance from the crop to the paired ceca and between the two ceca. No significant variation in morphology was observed between sex within any species We hope our work motivates other researcher to engage the hunting community in efforts to advance our understanding of variation in wildlife digestive system morphologies, generating new insights into the natural history of diverse species.

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Faculty Advisor

Diana Lafferty

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Grace Freitag is a McNair Scholar