Natal dispersal is assumed to be a particularly risky movement behavior as individuals transfer, often long distances, from birth site to site of potential first reproduction. Though, because this behavior persists in populations, it is assumed that dispersal increases the fitness of individuals despite the potential for increased risk of mortality. The extent of dispersal risk, however, has rarely been tested, especially for large mammals. Therefore, we aimed to test the relationship between dispersal and...

Human runners have long been thought to have the ability to consume a near constant amount of energy per distance traveled regardless of speed, allowing speed to be adapted to particular task demands with minimal energetic consequence. However, recent and more precise laboratory measures indicate that humans may in fact have an energy-optimal running speed. Here we characterize runners’ speeds in a free-living environment and determine if preferred speed is consistent with task or energy...

The study of song development has focused on temperate zone birds in which typically only males sing. In the bay wren, Cantorchilus nigricapillus, both sexes sing, performing precisely timed, female-initiated duets in which birds alternate sex-specific song phrases. We investigated the origin of these sex differences by collecting bay wren eggs and nestlings and hand-raising them in individual acoustic isolation chambers. Each bird was tutored with either monophonic or stereophonic recordings of bay wren duets,...