Between individual variation in risk-taking behavior and its life history consequences

Abstract

Flight initiation distances (FIDs) of animals approached by a potential predator provide information about the risk that individuals are willing to take given their state and the environment. Species differ in mean and variance in FID, suggesting that species with a large variance in FID have individuals that take either small or great risks, whereas species with a small variance are composed of individuals that are homogeneous in their risk-taking behavior. Here, we investigate the correlations between interspecific variance in risk-taking behavior and habitat selection, breeding range and population size, dispersal, and life history. Greater between individual variation in risk-taking behavior for a given average level of risk taking would imply that more different habitats could be exploited, resulting in larger local and global population sizes and larger ranges. There should be a link between dispersal distances and FID because individuals of risk-averse species should encounter greater difficulties of finding suitable breeding habitats. High local and global population sizes should select for fast life histories with early age at first reproduction, high annual fecundity, low juvenile survival, and fast rates of senescence in species with variable FIDs. Finally, a greater diversity of habitat use should select for a longer reproductive season in species with more variable FIDs. Analyses of FIDs for 133 species of birds revealed results largely consistent with these predictions. Because risk taking correlates with other kinds of behavior that constitute a syndrome behavioral syndromes can play an important role in producing ecological syndromes (i.e., correlations between ecological traits).