Bryan and Cherry Alexander / Chinstrap penguins (Pygoscelis antarctica) on a blue iceberg, with Antarctic Prion (Pachyptila desolata) flying over. Antarctica

David Tipling / Antarctic prion (Pachyptila desolata) in flight over Southern Ocean off South Georgia, January

Brent Stephenson / Antarctic prion (Pachyptila desolata) taking off from sea, South Atlantic, January.

Brent Stephenson / Antarctic prion (Pachyptila desolata) flying just over sea surface, South Atlantic, December.

Dave Watts / Fairy prion (Pachyptila turtur) on ground, Tasmania, Australia.

Brent Stephenson / Antarctic prion (Pachyptila desolata) in flight low over the sea, showing upperwing pattern. Between the Falkland Islands and South Georgia, South Atlantic. January.

Brent Stephenson / Antarctic prion (Pachyptila desolata) taking off from the sea, showing underwing pattern. Off South Georgia, South Atlantic. January.

Brent Stephenson / Fairy prion (Pachyptila turtur) in flight low over the sea, showing underwing pattern. Hauraki Gulf, Auckland, New Zealand, October.

Brent Stephenson / White-faced storm-petrels (Pelagodroma marina) feeding with fairy prions (Pachyptila turtur) over a school of fish. Hauraki Gulf, Auckland, New Zealand, December.