Abstract
Creching behaviour was monitored in 6 colonies of Adelie penguins at Cape Bird, Antarctica. Chicks were first left unguarded at a mean age of 22 days, but were susceptible to skua predation until 30 days old. The presence of adults deterred skuas. The probability of creching was inversely related to the number of adults present in a colony relative to the number of chicks. This suggests that creching serves as an alternate defence against predators when too few adults are present to deter skuas effectively. Creching did not vary consistently with mild fluctuations of climatic variables, but the proportion of chicks in contact with each other was greatest when relative humidity, wind speed, and cloud cover were highest and temperature was lowest.