Repeatability of alert and flight initiation distances in king penguins: Effects of colony, approach speed, and weather

Alert distance (AD) and flight initiation distance (FID) are popular measures used to explore the reaction of prey to approaching predators, and thus the economics underlying optimal escape strategies. AD likely mirrors the effort invested into vigilance, while FID provides an estimate of the perceived risk of an approaching threat. Although individual variation in AD and FID is influenced by environmental factors such as variation in predation pressure and human disturbance, the repeatabilities of these traits (especially AD), and therefore their designation as personality traits, remain under-investigated. Here, we studied the repeatability of AD, FID, and the decision to flee in a flightless, ground-breeding seabird, the king penguin (Aptenodytes patagonicus). A single experimenter approached three times over three consecutive days 47 incubating king penguins from two different colonies with varying human disturbance levels. We explored the effects of weather, time of day, and approach speed of the experimenter on these behaviors. Weather had an effect on all three behaviors. In warm, sunny weather AD increased. In rainy, windy weather birds were more likely to flee, but waited longer before initiating flight. Faster approach speeds between AD and FID increased FID. Weather conditions and speed of approach affected repeatability estimates, highlighting the need to consider external sources of variation when refining such estimates. FID and the decision to flee were significantly and moderately repeatable (r = 0.26 and 0.57, respectively), while AD was not. There was no evidence of behavioral habituation or sensitization in either colony.