Meeting Abstract

133.5  Monday, Jan. 7  Predation correlates of locomotor ontogeny among altricial bird species in Arizona and Borneo: Relative development at fledging DIAL, KP*; MARTIN, TE; Univ. of Montana, Missoula; Univ. of Montana, Missoula kdial@mso.umt.edu

Locomotor ontogeny among species is incredibly diverse and could be under strong selection from environmental pressures like predation risk. Laboratory studies on precocial species have demonstrated that dramatic differences exist in the rate of development between the forelimbs and hindlimbs, with correspondingly different capacities of locomotor performance. Does such variation in locomotor ontogeny change with level of predation in the natural environment? In this study, we explore variation in locomotor ontogeny among altricial songbirds that show a wide range in fledging time (8-18 days) and in their risk of nest predation associated with different nest types (e.g., ground, off-ground, and cavity). We find that in two very different environments, north temperate (northern Arizona) and tropical (Borneo, Malaysia), species with relatively high predation risk develop their locomotor appendages fast but fledge early when locomotor appendages are relatively small. In contrast, species that have relatively low risk of predation develop slower but prolong their stay in the nest and fledge with much more fully developed wings and legs. Such differences lead to variation in wing loading and performance and provide novel insight into the developmental tradeoffs that influence the evolution of avian diversity.