Foraging Habits as Predictors of Morphology in Raptor Communities Worldwide
The diurnal birds of prey commonly known as raptors play key ecosystem roles as apex predators and carrion eating nutrient cyclers (Donázar 2016, Sekercioglu 2006). These birds also show a wide distribution of morphological traits, particularly differences in feet, beaks, and wings. Previous work has established general connections between functional ecology and morphology, but finer level discrimination on a large scale has yet to be investigated (Pigot , 2020). Through completing a database of various ecological characteristics of all extant raptor species and binding these data to a collection of linear measurements of these birds, I was able to assess large scale correlations between form and function. I specifically focused on the ecological characteristics of prey size and carrion eating, both obligate and facultative. Data were organized into eight different data sets based on species’ range maps: North America, South America, Europe, Africa, Australia, Western and Eastern hemispheres, and worldwide. Canonical variates analyses (CVA) were performed on each dataset for each variable and used to determine how accurately the prey size or carrion eating status of a species could be predicted by its morphology. Multivariate analyses of variance (MANOVA) were then performed to determine if variables had a significant impact on morphology. MANOVAs and ANOVAs were also used to assess any differences between regions. Prey size, facultative, and obligate carrion eating were all found to be significant, accurate predictors of raptor morphology. Obligate carrion eating was most strongly tied to morphology; a species could be correctly classified as an obligate carrion eater by its morphology 88.9% of the time in the worldwide dataset. Low p-values from MANOVAs indicated that there were significant differences in morphology between all prey size categories and between different types of carrion eaters. Though larger regional data sets (worldwide, E/W hemispheres) still had significant correlations between morphology and ecological function, predictability percentages were higher for individual continents. These results indicate that, within these clades of birds, prey size and carrion eating are effective predictors of morphology. Although there certainly exists overlap of morphology between members of these feeding characteristic groups, these traits are still distinct enough to predict morphology most of the time.