Evaluating stress in a Hawaiian honeycreeper, Paroreomyza montana, following translocation

Abstract

Abstract We used differential counts of white blood cells to determine heterophil:lymphocyte ratios in the Maui Creeper (Paroreomyza montana), an endemic, non-endangered Hawaiian honeycreeper, as a measure of stress in response to varying distance and handling technique during translocations. The Maui Creeper was used as an in situ experimental model for the Po'ouli (Melamprosops phaeosoma), an endangered species for whom translocation is critical for its recovery. We translocated 18 Maui Creepers across rugged terrain by hand-carrying individual birds for two distances (1.0 or 2.5 km) inside portable containers. We tested two methods of confinement that varied in the degree of physical restraint during translocation. Birds translocated across longer distances developed significantly higher heterophil:lymphocyte ratios than those moved shorter distances. However, no significant difference was seen between container types. Our findings build on a previous study of stress response in passerines, and indicate that using heterophil:lymphocyte ratios to measure stress may be a valuable tool for evaluating management practices for other critically endangered passerines.