The giant petrels are known as the vultures of the Southern Ocean and can be seen scavenging off the coast in Kaikōura. These petrels are a pelagic (oceanic) species of bird. They are the largest of the petrels and there are two different species. The most common species that we see in Kaikōura is the northern giant petrel which can be seen here all year round. Once the winter months arrive we also see the southern giant petrel.
There are a few differences between the two and the main way to see the difference is looking at the colouration of their beak. The northern giant petrel has a brown/red tip at the end of their beak whereas the southern giant petrel has a blue/green tip.
They are scavengers and feed mainly on carrion floating on the surface. They can be very aggressive, especially when they are protecting their food against other birds. Being the main scavenger of the Antarctic waters they can eat anything from penguins and seal carrion, fish and squid.
They even have the ability to catch and kill other animals such as penguins and other seabirds. They are also one of the few petrel species that would feed on carrion on land.
With a keen sense of smell they have the ability to smell food from great distances! This helps them locate their prey out in the open ocean.
Northern giant petrel:
Photo Credit: Annika Dahlberg
Photo Credit: Annika Dahlberg
The northern giant petrel can be as heavy as 5 kg with a length (beak to tail) of 95 cm and a wingspan up to 2 m. They are generally found quite far south, from the sub Antarctic islands to the open oceans of the Antarctic. They breed widely on remote islands throughout the Southern Ocean. In NZ they breed on Auckland, Campbell, Antipodes and Chatham Islands. These birds can commonly be seen on our tours and at times just upon leaving the channel from our marina. The northern giant petrels often follow fishing boats and they can be seen following the local fishing boats here in Kaikōura and sit just outside the marina!
Southern giant petrel Photo Credit: Annika Dahlberg
Southern giant petrel in white morph. Photo: Allan Cronin
White morph resting on surface. Photo: Annika Dahlberg
The southern giant petrel is the larger of the two and they can be as heavy as 5 kg and a length (beak to tail) of 1 m and a wingspan of up to 2 m. Can be found breeding on Macquarie island and all the way down on mainland Antarctica. They can be seen in two different variants. They can morph into a white plumage with distinct black spots along their feathers. Only the southern giant petrel morphs into white and only about 10% of them do so.
As we only see the southern giant petrel in winter and very few of these are white morphs you have to be very lucky to see one in Kaikoura!
Giant petrels are a tube-nosed seabird and their tubes are particularly long. This helps the birds to pick up scents as their sense of smell is extremely good. These tubes have another important feature; they work as a drain to drain away any excess salt. Rather than drinking fresh water, they drink salt water and filter out the salt through glands that are located just above their eyes.
The biggest threat to giant petrels is longline fishing. They catch the longline fishing hooks as they are attracted to the bait and get caught and drown. They also face many other threats such as; climate change, ingesting plastic and oil spills.