The world's most southerly bird has become a threat to planes in Antarctica after developing a love for sitting on warm, snow-free airstrips.
Air traffic experts are seeking ways to scare off the south polar skuas, a large and aggressive brown seabird, but without harming them. They are a hazard because bird strikes can down aircraft.
The birds are protected by the 47-nation Antarctic Treaty, which declares the frozen continent a nature reserve.
At the British Rothera research station on the Antarctic Peninsula, about 100 skuas often sit on the 900-metre gravel runway. The odd penguin or seals can also be hazards.
As part of the skua scaring ritual, large bangs are set off and then a runway worker drives a six-wheeled vehicle up and down the runway, swerving towards any remaining birds. Sirens wail to alert both skuas and people.
At Davis, an Australian Antarctic base, staff take a different tack by feeding the birds to try to lure them away from the airstrip.
No birds have been hit this season at Rothera but there were minor strikes last year.
Meanwhile, the pilot commanding the US Airways jet that crashed into the Hudson River on Thursday told air traffic controlers seconds earlier that he lost all power after hitting birds, investigators confirmed.