The relationship between claw morphology and predatory ecology in birds of prey
Mentor 1
Chris Noto
Location
Union Wisconsin Room
Start Date
24-4-2015 10:30 AM
End Date
24-4-2015 11:45 AM
Description
Birds of Prey, also known as Raptors, differ in their ecology. Previous work has found relationships between claw curvature and predatory behavior, however it has not considered overall differences in claw shape between species. A sample of 167 claws from 15 species including diurnal and nocturnal raptors was collected from the Field Museum of Natural History (Chicago) and North Carolina Museum of Natural Sciences (Raleigh). X-ray images were taken in lateral view, and a series of 14 coplanar landmarks were place on each claw using TPSdig. The relationship between shape data and ecological variables were explored using MorphoJ software. Analyses included Principle Component Analysis (PCA), Canonical Variates Analysis (CVA) and a two-block Partial Least Squares (PLS). The majority of variations in claw shape occurs in the shape of the tubercle, nail curvature, and the proportion of nail length and body size in the claw. The PCA showed that the flexor tubercle and depth of the nail body yield the most change in claw morphology. The CVA presented a relationship between claw morphology and raptor mass, wingspan, length, and prey mass. Linear variables, such as raptor body length, were found not as significant as other variables. The results show that claw characteristics of certain species also correlate with ecological factors and hunting strategies. The correlation between claw shape and prey mass show that species with a deeper tubercle and smaller nail angle are significantly related to a larger prey mass. In addition, species that have a smaller prey mass have a different claw morphology: shallow tubercle and large nail angle. Prey mass may be more important than the actual prey identity, as there is considerable overlap among the different prey types. The PLS results suggest that particular combinations of nail and body shape covary, which is related to predatory strategy. One species, Pandion haliaetus (osprey), is significantly different from all other species in the sample. Ospreys are piscivores that have a specialized hunting strategy; however, they are also the largest species in this sample, which may affect the results. This research further elucidates the relationship between claw shape and hunting behavior in birds of prey. These results may also be used to make inferences about predatory behavior in theropod dinosaurs, which are close relatives of birds. /
The relationship between claw morphology and predatory ecology in birds of prey
Union Wisconsin Room
Birds of Prey, also known as Raptors, differ in their ecology. Previous work has found relationships between claw curvature and predatory behavior, however it has not considered overall differences in claw shape between species. A sample of 167 claws from 15 species including diurnal and nocturnal raptors was collected from the Field Museum of Natural History (Chicago) and North Carolina Museum of Natural Sciences (Raleigh). X-ray images were taken in lateral view, and a series of 14 coplanar landmarks were place on each claw using TPSdig. The relationship between shape data and ecological variables were explored using MorphoJ software. Analyses included Principle Component Analysis (PCA), Canonical Variates Analysis (CVA) and a two-block Partial Least Squares (PLS). The majority of variations in claw shape occurs in the shape of the tubercle, nail curvature, and the proportion of nail length and body size in the claw. The PCA showed that the flexor tubercle and depth of the nail body yield the most change in claw morphology. The CVA presented a relationship between claw morphology and raptor mass, wingspan, length, and prey mass. Linear variables, such as raptor body length, were found not as significant as other variables. The results show that claw characteristics of certain species also correlate with ecological factors and hunting strategies. The correlation between claw shape and prey mass show that species with a deeper tubercle and smaller nail angle are significantly related to a larger prey mass. In addition, species that have a smaller prey mass have a different claw morphology: shallow tubercle and large nail angle. Prey mass may be more important than the actual prey identity, as there is considerable overlap among the different prey types. The PLS results suggest that particular combinations of nail and body shape covary, which is related to predatory strategy. One species, Pandion haliaetus (osprey), is significantly different from all other species in the sample. Ospreys are piscivores that have a specialized hunting strategy; however, they are also the largest species in this sample, which may affect the results. This research further elucidates the relationship between claw shape and hunting behavior in birds of prey. These results may also be used to make inferences about predatory behavior in theropod dinosaurs, which are close relatives of birds. /
