Birds of the Snares Islands

Four Te Papa staff members visited the Snares Islands Nature Reserve for a fortnight in late 2013, undertaking a variety of seabird and plant research projects (see previous blogs listed below). The Snares Islands are famous for their birdlife, and here vertebrates curator Colin Miskelly looks at some of the species that are unique to the islands, or have strongholds there.

The Snares Islands viewed from the Western Chain; Tahi and Rua Islets in the foreground, North East and Broughton Islands in the distance. Image: Colin Miskelly, Te Papa

The Snares Islands viewed from the Western Chain; Tahi and Rua Islets in the foreground, North East and Broughton Islands in the distance. Image: Colin Miskelly, Te Papa

The islands lie 105 km south-southwest of Stewart Island, and were originally named simply ‘The Snares’ by Captain George Vancouver when he discovered them in November 1791. Vancouver considered the islands to be a hazard to shipping, hence the sinister name. The two main islands are covered with tree-daisy forest and tussock grassland. As the islands have never had introduced mammals establish, the wildlife is both abundant and approachable.

Sooty shearwaters returning to their breeding sites at dusk, Snares Islands. Image: Colin Miskelly, Te Papa

Sooty shearwaters returning to their breeding sites at dusk, Snares Islands, December 2013. Image: Colin Miskelly, Te Papa

The bird fauna is dominated by seabirds, particularly the phenomenally abundant sooty shearwater, which nests in burrows wherever the soil is deep enough. A previous blog described how the Te Papa team re-surveyed the size of the Snares Islands sooty shearwater population, and also illustrated the four other burrow-nesting petrel species present. These five petrel species (sooty shearwater, mottled petrel, common diving petrel, fairy prion and broad-billed prion) all visit their burrows at night, and so it is other species of seabirds that are most conspicuous during the day.

Snares crested penguins on the landing rocks in Station Cove. Image: Colin Miskelly: Te Papa

Snares crested penguins on the landing rocks in Station Cove, December 2013. Image: Colin Miskelly: Te Papa

Perhaps the most well-known bird species on the islands is the Snares crested penguin. As its name suggests, it breeds only within the Snares Islands, where it breeds on the two main islands (North East Island and Broughton Island), plus on two islets of the Western Chain, 5 km to the south-west. One of the enduring mysteries of Snares Island birdlife is why the crested penguins on the Western Chain breed six weeks later than those on the main island – are they a cryptic species awaiting ‘discovery’?

Snares crested penguin chicks on North East Island, 2 December 2013. Image: Colin Miskelly

Snares crested penguin chicks (and two adults) on North East Island, 2 December 2013. Image: Colin Miskelly, Te Papa

A pair of Snares crested penguins incubating eggs on Toru Islet, Western Chain, 28 November 2013. Image: Colin Miskelly, Te Papa

A pair of Snares crested penguins incubating eggs on Toru Islet, Western Chain, 28 November 2013. Image: Colin Miskelly, Te Papa

The two main species of albatross that breed on the Snares Islands are Buller’s mollymawk and Salvin’s mollymawk. The smaller Buller’s mollymawk breeds on any island or islet in the group that has at least some vegetation, while Salvin’s mollymawks nest solely on two islets of the rocky Western Chain (Toru & Rima Islets – the same islets as the penguins). About 8700 pairs of Buller’s mollymawks breed on the Snares Islands, laying mainly in January-February, with chicks departing during August-October. We were on the islands during the short gap between breeding seasons, and saw only a few early birds returning to reclaim their nest sites. In contrast, the Salvin’s mollymawks had downy chicks when we landed on Toru Islet on 28 November. While the Snares Islands are a major breeding site for Buller’s mollymawk, the main Salvin’s mollymawk breeding site is on the Bounty Islands about 900 km east of the Snares.

An adult male Buller's mollymawk on North East Island, Snares Islands, December 2013. Image: Colin Miskelly, Te Papa

An adult male Buller’s mollymawk on North East Island, Snares Islands, December 2013. Image: Colin Miskelly, Te Papa

A Salvin's mollymawk broods its chick on Toru Islet, Western Chain, Snares Islands, November 2013. Image: Colin Miskelly, Te Papa

A Salvin’s mollymawk broods its chick on Toru Islet, Western Chain, Snares Islands, November 2013. Image: Colin Miskelly, Te Papa

Unlike the other small petrels on the Snares, which nest out-of-sight in burrows and rock crevices, the Cape petrel nests mainly in the open on cliff ledges. This would make the adults and chicks vulnerable to predators, especially skuas, but the Cape petrels have a very effective anti-predator response. They vomit smelly stomach oil with sufficient accuracy and range to deter predators or people from approaching too close.

A Cape petrel on its cliff ledge nest, North East Island, Snares Islands, December 2013. Image: Colin Miskelly, Te Papa

A Cape petrel on its cliff ledge nest, North East Island, Snares Islands, December 2013. Image: Colin Miskelly, Te Papa

The top predator on the Snares Islands is the subantarctic skua, which looks similar to a large, heavily-built gull. During the breeding season skuas feed almost entirely on seabirds, particularly the five burrow-nesting petrel species. The Te Papa team put a lot of effort into locating and identifying skua prey remains in an effort to see whether the proportion of broad-billed prions consumed had declined since the massive prion mortality event that occurred in July 2011.

Subantarctic skuas squabble over the corpse of a sooty shearwater, Skua Point, Snares Islands, November 2013. Image: Colin Miskelly, Te Papa

Subantarctic skuas squabble over the corpse of a sooty shearwater, Skua Point, Snares Islands, November 2013. Image: Colin Miskelly, Te Papa

Antarctic terns breed as isolated pairs or in small colonies around the Snares Islands coastline, stridently and aggressively defending their nest sites from skuas and gulls. These striking birds breed on all of New Zealand’s subantarctic islands, plus on some of the muttonbird islands south-west of Stewart Island. Somewhat surprisingly, they have never been recorded from the North or South Islands only a short distance away.

An Antarctic tern in breeding plumage, Snares Islands, December 2013. Image: Colin Miskelly, Te Papa

An Antarctic tern in breeding plumage, Snares Islands, December 2013. Image: Colin Miskelly, Te Papa

Fernbirds on the main islands of New Zealand stay mainly among dense wetland vegetation. However, the endemic Snares Island subspecies spends much of its time in the open, busily foraging on the ground. They are fearless of larger animals, often walking over resting New Zealand sea lions to catch blowflies. While they frequently fly short distances, it is unusual to see a Snares Island fernbird fly more than 10 metres.

A recently fledged Snares Island fernbird foraging on the ground, December 2013. Image: Colin Miskelly, Te Papa

A recently fledged Snares Island fernbird foraging on the ground, December 2013. Image: Colin Miskelly, Te Papa

Adult Snares Island tomtit (not to be confused with the similar-looking black robin of the Chatham Islands). Image: Colin Miskelly, Te Papa

Adult Snares Island tomtit (not to be confused with the similar-looking black robin of the Chatham Islands). Image: Colin Miskelly, Te Papa

The endemic Snares Island tomtit is easily distinguished from other populations of New Zealand tomtits by its all-dark plumage. Both the tomtit and fernbird are common along the shoreline of the sheltered east coast of the Snares Islands, and so are readily seen by ecotourists zodiac-cruising close offshore. The Department of Conservation administers the Snares Islands Nature Reserve, and landing permits are limited mainly to conservation managers and approved researchers. Tourists visiting the islands are able to see much of the wildlife from zodiacs, as well as exploring spectacular sea caves and tunnels.

Tourists on a zodiac cruise along the eastern shoreline of the Snares Islands. Image: Colin Miskelly

Tourists on a zodiac cruise along the eastern shoreline of the Snares Islands. Image: Colin Miskelly

The most secretive of the Snares Island endemic birds is the Snares Island snipe – a bird that I have a particular fondness for. I had the privilege of studying snipe (mainly on the Snares) for my PhD thesis, and in 2005 participated in a translocation of snipe from the Snares Islands to Putauhinu Island (a muttonbird island south-west of Stewart Island). Snipe formerly occurred throughout the main islands of New Zealand, but their vulnerability to introduced predators has resulted in their current restricted distribution on a few outlying islands.

Snares Island snipe and chick, December 2013. Image: Colin Miskelly, Te Papa

Snares Island snipe and chick, December 2013. Image: Colin Miskelly, Te Papa

 

For more information, see Birds of the Snares Islands, New Zealand.

Te Papa Snares Islands blogs

Life through a burrowscope lens (Part 3) – subterranean Snares Islands

Were broad-billed prions from The Snares part of the massive die-off of this species in 2011?

Critters of the Snares Islands

Snares Island Flora – an introduction

Snares Islands Flora – the ferns

Snares Islands – 1947 and 2013 – In the footsteps of Edgar Stead (Part 11)

Western Chain, Snares Islands – 1929 and 2013 – In the footsteps of Edgar Stead (Part 10)

 

Science Live: Expedition Snares Island

4 Responses

  1. Glenda Rees

    So wonderful to see. Also some nice new species for NZBirdsonline, especially the tomtit, antarctic tern and snipe chick!!

    Reply
    • Colin Miskelly

      Thank you Olwen, Julia and Glenda for your comments.

      Yes, I should make time to load more of my own images on to NZ Birds Online!

      Cheers
      Colin

  2. Julia White

    I loved reading all about it as well, and I find the pictures superb, thank you.

    Reply
  3. Olwen Mason

    Really enjoyed this blog – very interesting.

    Reply

Leave a Reply

  • (will not be published)