Fairy prions are small petrels and their dove-like appearance gives them another name – dove petrels. In size, they are between Cook’s petrels and storm petrels, quite dainty birds, with pale grey plumage that has a soft blue cast. Across the upper surfaces of their wings and back they sport a distinctive dark ‘M’ marking. It’s been suggested that the cryptic grey plumage of many seabirds’ upperparts provide good camouflage at sea, particularly from birds such as skua, which can attack from above. In fact, the famous seabird scientist, Robert Cushman Murphy, suggested to the US navy in the early 20th century that the grey of the prion’s upperparts would provide good camouflage for warships. His advice was ignored, but after a series of tests, the colour finally chosen was an exact match for the plumage of a prion.
We see fairy prions in abundance in the Hauraki Gulf and along the Northland and Bay of Plenty coasts. Clouds of them can be seen feeding on small krill. This is mostly with other seabirds, such as fluttering and Buller’s shearwaters, red-billed gulls, and white-fronted terns. These birds feed in association with fish work-ups. But not always. You can find them feeding where there are strong tidal movements over reefs or through stacks and islands, such as at the Mokohinau, Hen & Chickens, and Poor Knights islands. These dense mobs of birds are very social and engage in a lot of chattering as they peck krill at the surface. They also feed on small fish and squid. However, like other petrels they can also dive. While snorkelling, we’ve filmed them diving in pursuit of something appealing.
Dense mobs of prions and shearwaters. Photo: Jono Irvine.
The fairy prion’s grey plumage provides good camouflage at sea. Photo: Richard Robinson (Depth NZ)
I’ve enjoyed watching these birds on many occasions. Once, north of Hauturu Little Barrier Island, while filming mixed trevally, kahawai and kingfish schools underwater, I was using a small inflatable to position a camera rig in front of the moving fish. The disturbed water was thick with krill. There were birds everywhere, moving with the fish. On a few occasions, their wings clipped me as they flew past (gentle taps) until I was well clear of the action. Another time, off North Cape in the Far North, we were riding in a launch with a huge wind behind us. It was a thrilling, rollicking ride as our launch surfed the big waves. Several of us seabirders were on the front deck, captivated by groups of prions flying alongside, effortlessly using the conditions to kick along with us.
The only place prions breed in northern New Zealand is on the Poor Knights islands. They nest in burrows, or in crevices amongst rocks, under forest or scrub. Like all species in the petrel family (which includes storm petrels, diving petrels, prions, petrels, shearwaters, and albatrosses) they raise one chick. With fairy prions, this will be over three months, including incubation and chick rearing duties, which is shared by both parents. They are starting to breed at this time of the year.
Fairy prions are one of a group of locally breeding seabirds that we are studying to assess the impact of changes in the marine environment. The seabirds’ time ashore allows us to study them on the many islands and headlands along our northern coasts. We study not only their breeding biology and populations on land, but also their foraging ecologies, diet and distributions at sea. As well as investigating their relationship to fish work-ups and potential prey species. Seabirds are crucial components of marine ecosystems and possess attributes that make them useful as indicators of change in the marine environment. Their populations are a key indicator for the long-term assessment of marine ecosystems.
by Chris Gaskin