A new bird for New Zealand – black-naped tern

A new bird for New Zealand – black-naped tern

Cyclone Dovi was a Category 4 severe tropical cyclone that passed through New Caledonia before barreling into New Zealand during 12–14 February 2022. Many North Island residents were hit by gale-force winds, power outages, torrential rain and flooding. Curator Vertebrates Colin Miskelly describes a discovery that came along with it.

However, the storm had a silver-lining for bird-watchers, as it carried with it an unprecedented haul of vagrant tropical seabirds, including New Zealand’s second-ever bridled tern, and at least one each of great frigatebird, lesser frigatebird, brown noddy, and black noddy, that were all observed between the Far North and Whangarei.

A black white and brown bird sitting on a rock
The second bridled tern known from New Zealand, 90-mile Beach, February 2022. Photo by Scott Brooks, New Zealand Birds Online

The pick of the bunch

The most notable of these tropical rarities was a single black-naped tern that came ashore at the Muriwai gannet colony west of Auckland on the evening of 13 February. Hayden Pye was at the colony at dusk photographing the gannets, when he noticed a small, pale tern sheltering under a bush on the edge of the colony. He didn’t recognise the bird, and posted the following on the ‘NZ Bird Identification’ Facebook page:

“I saw this small tern at Muriwai Gannet Colony this evening and am having difficulty with the ID. It really doesn’t seem to match anything from NZ Birds Online, the NZ Merlin pack or my Field Guide to the Birds of New Zealand. I’ve looked a bit further online and it kind of looks like a black-naped tern. It matches the description from eBird: ‘Adults appear snow-white except for a thin black nape stripe that extends from the eye (often not very visible from a distance), black outer edge to outermost primary, and thin, long black bill.’ Maybe I’m missing something? Seen from northern platform in the north-west corner. It was behind a small bush. It briefly scurried away and was obscured by the cliff, but was back in the same position behind the bush a few minutes later.”

A mainly white and grey bird with a black headband sitting on gravel
New Zealand’s first black-naped tern. Muriwai, February 2022. Photo: Hayden Pye, New Zealand Birds Online

Hayden had indeed found a black-naped tern. As it was the first-ever for New Zealand, this explained why he couldn’t find it on New Zealand Birds Online or in his New Zealand bird field guide.

A sad end

Acting on Hayden Pye’s post, two other keen birders were at the site before dawn, hoping to add black-naped tern to their New Zealand lists. Alas, it was not to be. The bird looked unwell in Hayden’s images, and unfortunately, it had died overnight, in the same place that Hayden described seeing it. The tiny corpse was retrieved and donated to Auckland Museum as a research specimen.

Auckland Museum bird staff agreed to loan the specimen to Te Papa before it was prepared as a study skin, and so Alan Tennyson and I were able to examine it in detail (plus Ricardo Palma searched it unsuccessfully for ectoparasites).

A white bird with a black headband in mid dive with blue background
A healthy black-naped tern. Photo by Ken Glasson, New Zealand Birds Online

Picking over the evidence

The tern was emaciated, weighing only 66 g (with an expected weight of more than 100 g). Its short bill confirmed that it was the expected eastern subspecies, which is found in the tropical western Pacific Ocean, including around New Caledonia. The bird had a complicated wing and tail moult pattern, meaning that it was an adult, rather than a recently-fledged young bird.

Unique bird specimens in New Zealand museums

There are many examples where the first (and sometimes only) example of a rare vagrant bird has ended up in a New Zealand museum. In the days before binoculars and telephoto lenses (and protective wildlife legislation!), vagrant birds were often shot by naturalists, as the only way that a new bird could then be identified and verified.

Several vagrant seabirds are known from a single dead specimen found washed ashore on a beach (e.g. Cory’s shearwater, streaked shearwater, Newell’s shearwater and Bulwer’s petrel). New Zealand’s first northern shoveler was shot by a duck-hunter, the first plumed egret was shot by an illegal collector, while the only black-faced monarch was killed by a cat, and the only rose-crowned fruit-dove was killed by Biosecurity New Zealand.

However, the black-naped tern is perhaps a unique case where a new vagrant bird species was seen alive before succumbing to natural causes and being retrieved as a specimen. And Hayden Pye was the only naturalist who had the good fortune to see it alive.

A green bird in a cardboard box
New Zealand’s first rose-crowned fruit-dove before it was killed as a perceived biosecurity risk. Photo courtesy of Biosecurity New Zealand

Verification

Hayden submitted his images as part of an Unusual Bird Report to be considered by the Birds New Zealand Records Appraisal Committee. When combined with details obtained from the specimen after it died, it was a straightforward decision for the RAC to make. As a result, black-naped tern has been officially added to the New Zealand list.

A white-grey bird with a black headband standing on gravel
New Zealand’s first black-naped tern. Muriwai, February 2022. Photo by Hayden Pye, New Zealand Birds Online

Congratulations to Hayden Pye for his unique experience that resulted in a new bird species being added to the New Zealand list.

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