The nuthatch and the hare: Slow explorers dominate in a re-established population of the Brown-headed Nuthatch (Sitta pusilla) two decades later

Abstract

Animal behavior regularly has substantial effects on the outcomes of reintroduction efforts. Reintroduction involves capturing a subset of individuals from a source population and releasing them into novel environments where variation in retention rates, predation, and territory acquisition could affect the age-class structure, sex ratio, and genetic and phenotypic characteristics of restored populations. Exploratory behavior, quantified as the rate that individuals explore novel settings, is one such heritable trait that might be affected by translocation, especially given recent studies suggesting that exploratory behavior can predict the survival and retention of individuals in unfamiliar environments. To assess the potential effects that translocation may have on exploratory behavior, we compared exploratory behavior for three Brown-headed Nuthatch (Sitta pusilla) populations: (1) a population reintroduced to Everglades National Park in 1998; (2) a population close to the original source population, and (3) a distant control population in north Florida. Exploratory behavior was quantified by placing individuals (n=17 per population) in an exploratory chamber and comparing flights/hops, scanning events, thoroughness of exploration, and other movement behaviors. We found that individuals in the reintroduced population scanned less, conducted fewer flights/hops, and were more sedentary than individuals in the other populations. Our findings suggest a shift in the prevalence of personality types toward slow explorers has taken place in the 20 years since reintroduction, adding to other studies suggesting that slow explorers fare better in novel environments. Although the reintroduced population contained fewer fast-exploring individuals relative to the other populations studied, fast-explorer phenotypes may increase over time if they convey the fitness benefits described in other studies.