Summary
Creching emperor penguin (Aptenodytes forsteri) chicks were exposed to two overflights by a Sikorsky S-76, twin engine helicopter at 1000 m (3300 ft), a current operational guideline of the Australian Antarctic Division for helicopter activity in Antarctica. The flights were conducted on the same day but under different wind conditions: a morning flight with a 10-knot (18 km h-1) katabatic wind blowing perpendicular to the direction of helicopter travel, and an afternoon flight with virtually no wind. Background noise levels recorded in the morning before the helicopter flight were significantly higher than in the afternoon, but these differences were not detectable when the helicopter was overhead. There were also no significant differences in the way chicks responded to helicopters between the morning and afternoon flight. All chicks became more vigilant when the helicopter approached and 69% either walked or ran, generally moving less than 10 m toward other chicks (i.e. not scattering). Most chicks (83%) displayed flipper-flapping, probably indicating nervous apprehension. This behaviour was seldom displayed in the absence of disturbance. Although all effects were relatively transitory, the results support the introduction of a more conservative guideline of 1500 m (5000 ft) minimum overflight altitude for helicopter operations around breeding localities of this species.