Meeting Abstract

30.1  Monday, Jan. 4  Food supplementation promotes molt and not reproduction in a tropical bird CLASS, A.M.*; MOORE, I.T.; Virginia Tech; Virginia Tech classam@vt.edu

Tropical vertebrates typically exhibit a ‘slow pace of life’ syndrome relative to their higher latitude counterparts. Characteristics of this syndrome include delayed maturation, slowed aging, low fecundity and high annual survival. Following from this, it is predicted that individuals exhibiting the slow pace of life should trade current reproductive effort for maintenance, supporting survival and future reproduction. Recently, a meta-analysis of supplemental feeding studies found that birds typically advance reproductive initiation with extra food, and that the degree of advancement is negatively associated with latitude. However, there was only one tropical study in the meta-analysis. We conducted two food supplementation studies on tropical rufous-collared sparrows Zonotrichia capensis in the eastern Andes of Ecuador. In the first experiment, we supplemented territorial pairs during the non-breeding life history stage and in the second experiment we supplemented pairs that were provisioning fledglings. In both experiments food supplemented birds molted (replaced feathers) rather than investing further into reproduction. To our knowledge, this is the first study to experimentally show that a food supplemented bird invests in maintenance over reproduction. This result is consistent with a slow pace of life in the tropics and demonstrates a fundamental difference between tropical and temperate species.