Another extinct bird: Northland’s unique shag

Curator of vertebrates Alan Tennyson discusses another previously unknown New Zealand bird extinction, published in a new article today. 

Last month it was revealed that New Zealand had lost its unique swan in prehistoric times.

That list of extinctions continues to grow at an alarming rate as research, led by an Otago University team, published today reveals that New Zealand lost yet another bird in recent times – this time a shag.

New Zealand is the centre of global diversity for seabirds and we have more shags (also known as cormorants) than anywhere else (13 species).

The king shag is our rarest shag species. It is restricted to the Marlborough Sounds and classified as Nationally Endangered, with a global population of only a few hundred birds.

New Zealand king shags

New Zealand king shags, Marlborough Sounds. Photograph by Philip Griffin, courtesy of NZ Birds Online

It had long been known that bones of a species similar to the king shag can be found as far away as the top of the North Island but new DNA research, based on museum specimens, has now revealed that these bones were not from king shags but from an entirely unknown species – named today as Leucocarbo septentrionalis, the kohatu shag.

The name kohatu comes from the phrase ‘Te ao kohatu’, meaning ‘from the stone age before our time’ and was suggested by Northland’s Ngāti Kuri, as the bones were found in their rohe.

We know very little about this newly described extinct species. So far only a handful of its bones have been found in coastal dunes. These bones date back in age a few thousand years and, based on the history of better known extinct birds like moa, it can be assumed that the kohatu shag was hunted to extinction in prehistoric times.

Leg bone of a kohatu shag

The leg bone (femur) of a kohatu shag found in a Northland dune. Photograph by Alan Tennyson

As the extinct species was closely related to the king shag, both species probably looked quite similar but the bones show that the kohatu shag was slightly smaller.

S 034434 shag skull lateral raSkull of the holotype of the extinct kohatu shagesized for blog

Skull of the holotype of the extinct kohatu shag, found by Trevor Worthy. Photograph by Jean-Claude Stahl. Te Papa (S.34434)

The kohatu shag is New Zealand’s fourth known recently-extinct seabird – it joins the Waitaha penguin, Scarlett’s shearwater, and Imber’s petrel. The new discovery brings the total number of recently-extinct New Zealand birds to 56 and, unfortunately, it seems certain that on-going research will increase this number even further.

Read the full research paper

Rawlence NJ, Till CE, Easton LJ, Spencer HG, Schuckard R, Melville DS, Scofield RP, Tennyson AJD, Rayner MJ, Waters JM, Kennedy M (2017). Speciation, range contraction and extinction in the endemic New Zealand King Shag complex. Molecular Phylogenetics and Evolution.

2 Responses

  1. Alan Tennyson

    Thanks Barbara – studying ancient DNA is allowing us to re-examine a lot of questions about relationships of recently extinct birds. We have several other similar projects in progress, for example, looking at the penguin fossils from the Chatham Islands.

    Reply
  2. Barbara Hammonds

    Thanks for this, and the links to earlier posts on recently extinct birds. Very sad, and important to spread the word on this. I wonder what else will be revealed by the newer DNA techniques?

    Reply

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