Brent Stephenson / Northern giant petrel (Macronectes halli) moving through water, off Kaikoura, Canterbury, New Zealand, November.

Brent Stephenson / Northern Giant Petrel (Macronectes halli) with wings outstretched and tail cocked in threat display. Off Kaikoura, Canterbury, New Zealand, October.

Tony Heald / Northern Giant Petrel (Macronectes halli) attacking to feed on King penguin (Aptenodytes patagonicus) chick. Salisbury Plain, South Georgia. September.

Tony Heald / Northern giant petrel (Macronectes halli) running with wings outstretched, face bloodied. St Andrews Bay, South Georgia. October.

Tony Heald / Northern giant petrel (Macronectes halli) running in aggression with bloodied face. St Andrews Bay, South Georgia. October

Tony Heald / Northern giant petrel (Macronectes halli) running with bloodied beak, King penguins (Aptenodytes patagonicus) in background. St Andrews Bay, South Georgia. September.

Tony Heald / Southern giant petrel (Macronectes giganteus) fighting with Northern giant Petrel (Macronectes halli). Southern elephant seal (Mirounga leonina) male observing in background. St Andrews Bay, South Ge...

Tony Heald / Southern giant petrel (Macronectes giganteus) and Northern giant Petrel (Macronectes halli) fighting with beaks raised upwards. Southern elephant seal (Mirounga leonina) male observing in background....

Tony Heald / Northern Giant Petrel (Macronectes halli) Nesting amongst Tussock Grass Ocean Harbour South Georgia Is. South Atlantic October 2017

Rick Price / Northern giant petrels (Macronectes halli) feeding on a seal carcass, surrounded by Southern elephant seals (Mirounga leonina), Gild Harbour, South Georgia, Antarctica. October.

Rick Price / Two Northern giant petrels (Macronectes halli) on the water, one with a bloodied face from feeding on an elephant seal carcass, Gold Harbour, South Georgia, Antarctica. October.

Rick Price / Northern giant petrels (Macronectes halli) feeding on an elephant seal bull carcass, Peggoty Bluff, South Georgia, Antarctica. October.

Rick Price / Northern giant petrels (Macronectes halli) fighting over an elephant seal bull carcass, Peggoty Bluff, South Georgia, Antarctica. October.

Richard Robinson / Great white shark (Carcharodon carcharias) and two Northern giant petrel (Macronectes halli) feeding on a recently deceased Humpback whale (Megaptera novaeangliae) calf, around six metres long off the...

Richard Robinson / Great white shark (Carcharodon carcharias) and two Northern giant petrel (Macronectes halli) feeding on a recently deceased Humpback whale (Megaptera novaeangliae) calf, around six metres long off the...

Richard Robinson / Antipodean albatross (Diomedea antipodensis) and Northern giant petrel (Macronectes halli) feeding on a recently deceased Humpback whale (Megaptera novaeangliae) calf around six metres long with disti...

Mark Carwardine / Northern giant petrel (Macronectes halli) threatening another individual over dead seal carcass, Gold Harbour, South Georgia, November

Mark Carwardine / Northern giant petrel (Macronectes halli) fighting over dead seal carcass, Gold Harbour, South Georgia, November

Mark Carwardine / Northern giant petrel (Macronectes halli) rear view of bird displaying over dead seal carcass, Gold Harbour, South Georgia, November

Mark Carwardine / Northern giant petrel (Macronectes halli) displaying over dead seal carcass, Gold Harbour, South Georgia, November

Mark Carwardine / Northern giant petrel (Macronectes halli) fighting over dead seal carcass, Gold Harbour, South Georgia, November

Richard Robinson / Northern giant petrel (Macronectes halli) juvenile on ground, Enderby Island in the subantarctic Auckland Islands archipelago, New Zealand, January Editorial use only.

Richard Robinson / Northern giant petrel (Macronectes halli) juvenile on ground, Enderby Island in the subantarctic Auckland Islands archipelago, New Zealand, January Editorial use only.

Richard Robinson / Northern giant petrel (Macronectes halli) juvenile calling on ground, Enderby Island in the subantarctic Auckland Islands archipelago, New Zealand, January Editorial use only.

Richard Robinson / Northern giant petrel (Macronectes halli) in flight, Enderby Island in the subantarctic Auckland Islands archipelago, New Zealand, January Editorial use only.

Richard Robinson / Northern giant petrel (Macronectes halli) feeds on dead New Zealand sealion pup (Phocarctos hookeri) Enderby Island in the subantarctic Auckland Islands archipelago, New Zealand, January Editorial use...

Richard Robinson / Northern giant petrel (Macronectes halli) feeds on dead New Zealand sealion pup (Phocarctos hookeri) Enderby Island in the subantarctic Auckland Islands archipelago, New Zealand, January Editorial use...

Richard Robinson / Northern giant petrel (Macronectes halli) feeds on dead New Zealand sealion pup (Phocarctos hookeri) Enderby Island in the subantarctic Auckland Islands archipelago, New Zealand, January Editorial use...

Richard Robinson / Northern giant petrel (Macronectes halli) chick sits upon a bed of Acaena minor (var. antarctica) a prostrate dicotyledonous herb at Enderby Island in the subantarctic Auckland Islands archipelago, Ne...

Richard Robinson / A Northern giant petrel (Macronectes halli) feasts on a dead New Zealand sea lion (Phocarctos hookeri) at the Sandy Bay colony, Enderby Island, Auckland Islands archipelago, New Zealand. January 2016...

Richard Robinson / A Northern giant petrel (Macronectes halli) feasts on a dead New Zealand sea lion (Phocarctos hookeri) at the Sandy Bay colony, Enderby Island, Auckland Islands archipelago, New Zealand. January 2016...

Mark Carwardine / Northern Giant Petrel (Macronectes halli) pair fighting, Gold Harbor, South Georgia Island

Mark Carwardine / Northern Giant Petrel (Macronectes halli) pair fighting, Gold Harbor, South Georgia Island

Mark Carwardine / Northern Giant Petrel (Macronectes halli) displaying, Gold Harbor, South Georgia Island

Mark Carwardine / Northern Giant Petrel (Macronectes halli), Gold Harbor, South Georgia Island

Mark Carwardine / Northern Giant Petrel (Macronectes halli) fighting with Antarctic Giant Petrel (Macronectes giganteus), Gold Harbor, South Georgia Island

Chris & Monique Fallows / White capped albatross (Thalassarche steadi) fighting with Northern giant petrel (Macronectes halli), Kaikoura, New Zealand, March.

Chris & Monique Fallows / Wandering albatross (Diomedea exulans) and Northern giant petrel (Macronectes halli) squabbling, Kaikoura, New Zealand, March.

Brent Stephenson / Northern giant petrel (Macronectes halli) flying over sea, during moult in the outer wing, with several inner primaries/outer secondaries missing, South Atlantic, January.

Brent Stephenson / Northern Giant petrel (Macronectes halli) flying low over the sea, showing moult in the outer wing, with several inner primaries/outer secondaries missin, South Atlantic, January.

Brent Stephenson / Northern Giant petrel (Macronectes halli) in flight, South Atlantic, January.

Brent Stephenson / Northern giant petrel (Macronectes halli) in flight showing the underside of its wings, South Atlantic, January.

Brent Stephenson / Northern giant petrel (Macronectes halli) with wings stretched on water, off Kaikoura, Canterbury, New Zealand, November.

Brent Stephenson / Northern giant petrel (Macronectes halli) taking off from water. Off Kaikoura, Canterbury, New Zealand, November.

Theo Webb / Northern giant petrel (Macronectes halli) feeding on the carcass of a dead female Antarctic fur seal (Arctocephalus gazella) South Georgia Island.

Theo Webb / Northern giant petrel (Macronectes halli) South Georgia Island.

Sebastian Kennerknecht / Northern Giant Petrel (Macronectes halli) gliding over ocean, Kaikoura, South Island, New Zealand

Sebastian Kennerknecht / Northern Giant Petrel (Macronectes halli) gliding over ocean, Kaikoura, South Island, New Zealand

Sebastian Kennerknecht / Northern Giant Petrel (Macronectes halli) pair fighting, Kaikoura, South Island, New Zealand, sequence 4 of 5

Sebastian Kennerknecht / Northern Giant Petrel (Macronectes halli) pair fighting, Kaikoura, South Island, New Zealand, sequence 3 of 5

Chris & Monique Fallows / Northern Giant Petrel (Macronectes halli) in flight, Southern Ocean.

Brent Stephenson / Northern giant petrel (Macronectes halli) flying at sea with land in the background, Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Two New Zealand Albatross (Diomedea antipodensis) feeding at the sea surface, surrounded by Northern Giant Petrels (Macronectes halli) and Cape Petrels (Daption capense australe). Off Kaikoura, Canter...

Brent Stephenson / New Zealand Albatross (Diomedea antipodensis) feeding at the sea surface, surrounded by Northern Giant Petrels (Macronectes halli) and Cape Petrels (Daption capense australe). Off Kaikoura, Canterbury...

Brent Stephenson / Two New Zealand Albatross (Diomedea antipodensis) feed with wings raised, surrounded by Northern Giant Petrels (Macronectes halli) and Cape petrels (Daption capense australe). Off Kaikoura, Canterbury...

Brent Stephenson / Northern giant petrels (Macronectes halli) fighting over food. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Northern Giant Petrels (Macronectes halli) fighting over food. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Northern Giant Petrels (Macronectes halli) fighting over food. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Northern Giant Petrel (Macronectes halli) resting on water. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Northern Giant Petrel (Macronectes halli) sitting on the water calling with bill open. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Northern Giant Petrel (Macronectes halli) in flight low to the water. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Northern Giant Petrel (Macronectes halli) taking off from water. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Northern Giant Petrel (Macronectes halli) immature with wings outstretched and tail cocked in threat display. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Northern Giant Petrel (Macronectes halli) adjusting its wings sitting on the water. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / New Zealand Albatross (Diomedea antipodensis) feeding at the sea surface, surrounded by Northern Giant Petrels (Macronectes halli) and Cape Petrels (Daption capense australe). Off Kaikoura, Canterbury...

Brent Stephenson / Northern Giant Petrel (Macronectes halli) about to land on the water. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Northern Giant Petrel (Macronectes halli) resting on the water. Off Kaikoura, Canterbury, New Zealand, October.

Brent Stephenson / Two immature Northern Giant Petrels (Macronectes halli) fighting over food. Off Kaikoura, Canterbury, New Zealand, October.

Mike Read / Northern / Hall's giant petrels (Macronectes halli) fighting for food, New Zealand

Mike Read / Northern / Hall's giant petrels (Macronectes halli) fighting for food, New Zealand

Mike Read / Northern / Hall's giant petrel (Macronectes halli) on the sea with wings raised, New Zealand

Charlie Summers / Nesting Southern / Hall's Giant Petrel (Macronectes halli). Prion Island, South Georgia, January.

Tim Laman / Northern / Hall's giant petrel (Macronectes halli) in flight over the Drake Passage, Southern Ocean, January

Tim Laman / Northern / Hall's giant petrel (Macronectes halli) in flight over the Drake Passage, Southern Ocean, January

Hanne & Jens Eriksen / Northern / Hall's giant petrel {Macronectes halli} in flight, Scotia Ridge, South Atlantic

Hanne & Jens Eriksen / Hall's giant petrel {Macronectes halli} close-up, Gold Harbour, South Georgia

Andrew Walmsley / Northern / Hall's giant petrel (Macronectes halli) portrait with Cape pigeons in background, Kaikoura, South Island, New Zealand, October

Roy Mangersnes / Northern / Hall's giant petrel (Macronectes halli) in threat posture, Gold Harbour, Southern Ocean, Antarctica. November

Roy Mangersnes / Northern / Hall's (Macronectes halli) and Southern Giant Petrels (Macronectes giganteus) fighting over a seal carcass at Gold Harbour, Southern Ocean, Antarctica. November

Roy Mangersnes / Northern giant petrel (right) {Macronectes halli} and Southern giant petrel (left) (Macronectes giganteus) fighting over a seal carcass, Gold Harbour, Southern Ocean, Antarctica. November

Roy Mangersnes / Northern / Hall's giant petrel (Macronectes halli) in threat posture, Gold Harbour, Southern Ocean, Antarctica. November

Yva Momatiuk & John Eastcott / Northern Giant Petrel (Macronectes halli) flying low above ocean, Antarctic Convergence, Southern Ocean

Grant Dixon / Northern Giant Petrel (Macronectes halli) on nest with Mount Cunningham in the background, South Georgia Island, Antarctica

Mike Potts / Northern / Hall's giant petrel {Macronectes halli} Kaikoura, South Island, New Zealand

Pete Oxford / Northern Giant Petrel / Hall's giant petrel {Macronectes halli} head profile, Baie de Marin, Ile de Lapossession, Crozat Island, Southern Indian Ocean.

Tui De Roy / Northern Giant Petrel (Macronectes halli) stretching wings amid tussock grass, Antipodes Island, New Zealand

Tui De Roy / Northern Giant Petrel (Macronectes halli) chick begging parent for food, Antipodes Island, New Zealand

Hanne & Jens Eriksen / Hall's giant petrel {Macronectes halli} in flight, South Atlantic

Sebastian Kennerknecht / Northern Giant Petrel (Macronectes halli) on water, Kaikoura, South Island, New Zealand

Sebastian Kennerknecht / Northern Giant Petrel (Macronectes halli) flying, Kaikoura, South Island, New Zealand

Sebastian Kennerknecht / Northern Giant Petrel (Macronectes halli) pair fighting, Kaikoura, South Island, New Zealand, sequence 5 of 5

Sebastian Kennerknecht / Northern Giant Petrel (Macronectes halli) pair fighting, Kaikoura, South Island, New Zealand, sequence 2 of 5

Sebastian Kennerknecht / Northern Giant Petrel (Macronectes halli) pair fighting, Kaikoura, South Island, New Zealand, sequence 1 of 5

Konrad Wothe / Northern Giant Petrel (Macronectes halli) on water, South Georgia Island

Mike Potts / Two Northern / Hall's giant petrels (Macronectes halli) fighting over fish offal discarded from a fishing boat, off Kaikoura coast, South Island, New Zealand.