Northern Giant Petrel Release
By Karen Keeton

Sunday, 19th November 2023

We had the pleasure of releasing a Northern Giant Petrel (Macronectes halli) on 19th November 2023. The bird was admitted on the 13 November 2023 to SANCCOB Rehabilitation Centre. X-rays were taken and the bird examined, and no abnormalities were shown/found. We suspect the bird was blown off course. It was truly wonderful for our crew and guests to get such a closeup look at this large pelagic bird. The bird seemed to love being back in the water, splashing and dunking its head.

At SANCCOB, checked, healthy and waiting for his lift home.

A little of info about these big birds:

Northern Giant Petrels are found throughout the Southern Ocean, North of the Antarctic Converge/Antarctic Front, as far North as Chile, Argentina, South Africa, New Zealand and half of Australia. The genus name, Macronectes halli, combines the Ancient Greek makros meaning "great" and nēktēs meaning "swimmer". The name "petrel" refers to the Biblical account of Saint Peter walking on water, referring to the way these birds run on top of the water as they are taking off and becoming airborne.

The two giant petrel species, Northern and Southern, are tube-nosed petrels. All tube-noses have tubular nostrils, as can be seen in this pic below. These birds produce a stomach oil made up of a waxy compound and triglycerides that is stored in the proventriculus (the rod shaped organ, located between the oesophagus and the gizzard of most birds). This oil is sprayed out of their mouths as a defence against predators as well as an energy rich food source for chicks and for the adults during their long flights. These birds also have a salt gland that is situated above the nasal passage and helps desalinate their bodies, due to the high amount of sea water that they consume. They excrete a concentrated saline solution from their tube nostrils.

The Northern giant petrel averages 90 cm in length with a wingspan of 150 to 210 cm. Their sizes are variable, with males averaging about 3.6kg to 4.9 kg and females 2.8kg to 3.72 kg. Their weight can range from 2.5 to 5.8 kg. The plumage consists of grey-brown body with and a lighter coloured forehead, sides of face, and chin. Their bill is between 90 and 110 mm long and is pinkish yellow with a brown tip. The eyes are grey. The juveniles are entirely dark brown and lightens as they age.

The Northern giant petrel feeds mainly on dead penguins and seals, as well as fish, krill, squid, and other cephalopods such as a squid, octopus, cuttlefish, or nautilus. They will follow fishing boats and cruise ships, eating any discarded fish and waste. They are extremely aggressive birds and will kill other pelagic birds (mostly penguin chicks, sick or injured adult penguins and chicks of other seabirds), even those as large as an albatross.

These birds start breeding at an average age of 10 years, and breed on islands in colonies, which they share with the Southern Giant Petrel. During the breeding season, males eat more carrion (flesh from a carcasses) than females, with the females feeding on pelagic sources.

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