Meeting Abstract

70.6  Wednesday, Jan. 6  Precocial hindlimbs and altricial forelimbs of developing Mallard ducks: A study of locomotor performance and morphometrics DIAL, TR*; CARRIER, DR; University of Utah; University of Utah trdial@gmail.com

The young of some precocial species exhibit near-adult levels of locomotor performance. Waterfowl (Anseriformes) have an unusual developmental trajectory wherein their precocial hindlimbs exhibit the capacity for high levels of aquatic and terrestrial locomotion, whereas their forelimbs undergo a much more altricial trajectory. To gain a better understanding of the functional consequences of altricial versus precocial development I am investigating the locomotor ontogeny of Mallards (Anas platyrhyncos, n=80) from day of hatching to adulthood. Using high-speed video, maximal whole-body escape performance (acceleration and velocity) was quantified during running, swimming, flapping descent and takeoff across ontogeny. A growth series of morphological measurements was collected and directly compared to performance data. Long bone mid-shaft diameter and muscle mass scaled to body mass with negative allometry in the hindlimb, but with strong positive allometry in the forelimb. Hatchlings exhibited near-adult levels of hindlimb performance during swimming and running. In contrast, although the aerodynamic forces of excised and dried Mallard wings suggests a potential for early forelimb function, the forelimbs were unable to generate sufficient aerodynamic power for flight until the animals were adult size.