A winner is crowned

Pūkeko (Porphyrio porphyrio melanotus) from wikipedia

Forget bird of the week, here is bird of the year as voted by the New Zealand public (truthfully it was 7851 of them). This year it was taken out by the humble pūkeko (Porphyrio porphyrio melanotus). The pūkeko is a common rail that inhabits swamps and wetland, often seen at motorway verges. Sadly this tendency to hang out next to the motorway results in a fair number of deaths by car. Interestingly (to me at least), the pūkeko is a subspecies that belongs to a species complex with a broad distribution. Collectively known as the Purple Swamphen, the complex consists of 15 subspecies found in Europe, southeast Asia, Africa, New Guinea, Melanesia, western Polynesia, Australia and of course New Zealand. The Purple Swamphen is truly cosmopolitan. 

A takahē (Porphyrio hochstetteri)from here

In addition to the pūkeko, New Zealand is home to eight other species of rail. There is also evidence from middens that there were another eight species of endemic rails. But, as I have mentioned in previous posts on New Zealand birds (here and here), the arrival of humans resulted in their extinction. One species that was thought to be extinct, the takahē (Porphyrio mantelli hochstetteri), was 'miraculaously' rediscovered in 1948 G.B. Orbell. Orbell found a small population of about 250 indivuduals in a remote refuge in the Murchison, Kepler and Stuart Mountains in Fjordland on New Zealand's South Island. Following breeding and relocation efforts, takahē are now found on four predator-free offshore islands as well as at their rediscovery site.

Given their close relation to each other, the pūkeko and takahē are similar in appearance. Both species are bluish in colour with bright red legs and bills. However, the takahē is stockier and has a heavier bill. Furthermore, the takahē is flightless whereas the pūkeko is volant (i.e. it flies), albeit reluctantly, which is typical among rails. As with many New Zealand birds, and island birds in general, flightlessness is common and evolves in the absence of mammalian predators or competitors.

For some more pictures of pūkeko and other NZ native birds check out Chthoniid's Wildlife Photography and for some takahē videos check out the Deparment of Conservation. Also look out for a follow-up post on takahē that will be a little bit sciencier (that is a real word) demonstrating how modern genetic techniques have helped us learn so much more about species distributions. There is a hint about it in the species name for takahē.

Science journalism?

A recent paper published in Frontiers in Ecology and the Environment (Clements et al. 2011) and subsequent press releases in New Zealand has resulted in a some public backlash. The paper proposes a new index for assessing the extinction risk of a species called SAFE (species ability to forestall extinction). In the paper the authors tested the strength of the SAFE index at predicting the most commonly used species threat measure, the International Union for Conservation of Nature (IUCN) Red List, and found it to perform better than other currently used measures.

The SAFE index is really quite simple. It takes into account two things, the total number of individuals in a species across it's entire known range and, the minimum viable population (MVP) of a species. The minimum viable population is the lowest number of individuals a population needs to sustain itself. A few years ago a cross species review of MVP and found that on average MVPs are around 4169 individuals (Traill et al 2007). The importance of this with regard to extinctions is obvious. If a species population size drops below this minimum, the chances of extinction are greatly increased. See I told you it was simple.

Photo credit: Shane McInnes, winner of The Worlds Rarest Birds photo competition

However, the backlash in New Zealand about this work was largely from ill informed people who have a chip on their shoulder. What chip you ask? Well it so happens that the authors of the SAFE paper are based at Australian institutions. So what? Well the crux of the story stems from the misrepresentation of the work and how it can be applied in a real world situation. Professor Cory Bradshaw was one of the authors who worked on the paper and talked about the work on radio here in NZ. There were also some news articles, one entitled 'Let the wonderfully wierd kakapo die--scientist' specifically got me riled up. The kakapo (pictured above) is a very unique bird in that is a flightless, nocturnal parrot, the only one of its kind in the world, but like so many NZ birds, it is endangered. And according to the SAFE index, with only 131 individuals of the species left, it has little chance of being saved. Luckily there are a huge number of dedicated people, both paid and volunteers, who are trying to get this bird back on it's feet. What Corey Bradshaw had to say was what people hated. He said that the massive expenditure on saving a single species that fell short on the SAFE index is unjustified because, where financial resources are limited, this happens to the detriment of countless other species. The other species may not be endangered but could be on the verge and thus excluded from the conservation effort. Therefore, by the time we realize that these species are becoming rare it may be too late, one because we spent too much money on a single species and don't have much left, and two because they may already be below the MVP threshold. 


You could go and read some of the comments on the news article but I have picked out some of my favourites:

This one is priceless for a couple of reasons. Firstly they cite positive as people who are slandering Corey Bradshaw, and secondly he talks about Darwineans. I think what he means is darwinians, but I have no idea what he means by it, particularly when he talks about saving money etc.

Glad to see so many positive (save the Po) comments, but am surprised at the number who agree with the Aussie! NZ has saved a bird before, and hopefully we will do it again. To those of you "Darwineans" who are against "wasting money" saving it....think of all the money we waste trying to save other humans?? Is that a waste too? Should the NZ government let nature take its course next time you have a treatable illness or injury?

 Another classic. I love how she  calls him a "so-called 'scientist'". And then goes on to attack him because he is Australian. If she had not just read the crap title of the article and bothered to find out about the source material she would ave realised two things. One, that Corey Bradshaw is a "real" scientist who is highly published and respected in his field, and two, that he is in fact Canadian who now lives in Australia. Additionally, he did his PhD in New Zealand.

Please everyone, don't give this so-called 'scientist' another minute of our time. BUT, I guess if we don't, he will think "yeah, no one is commenting about my statement" so he'll think we really don't care about saving our lovely little kakapo. wrong !!!! Keep your Aussie BS to yourself....

 Comments about being Australian were really common. Here's a couple more. These ones are the most ridiculous. Real geniuses!

As many others have said, how about the Australians keep to their own country?! Australia has their own problems to watch out for!

Typical comment from an Australian i mean they have a history with there Native people as well.

The worst part about this is obvious slant the media took and by having a title like it did, peoples minds were made up for them before they actually had any understanding of the topic.

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Clements, G. R., Bradshaw, C. J. A., Brook, B. W., & Laurance, W. F. The SAFE index: using a threshold population target to measure relative species threat. Frontiers in Ecology and the Environment, preprint.

Traill, L. W., Bradshaw, C. J. A., & Brook, B. W. (2007). Minimum viable population size: A meta-analysis of 30 years of published estimates. Biological Conservation, 139(1-2), 159-166.

Light without flight

Stephens Island wren (Traversia lyalli) drawn by John Gerrard Keulemans

 This week's birds comes once again from New Zealand's extinct passerine birds fauna. I have previously posted about the heaviest bird capable of flight, the kori bustard. Today I introduce you to the Stephens Island wren (Traversia lyalli), weighing around 20 grams and the lighest  bird that is known to have been flightless. It was also one of only three known flightless passerines, all of which were island birds. Were, because sadly they are all extinct.

Flightlessness in birds is common on islands and is an artefact of an evolutionary history devoid of typically mammalian predators. This is evident in New Zealand which has the greatest number of flightless bird species than any other landmass. Subsequently, it is flightlessness that contributes significantly to predation vulnerability and ultimately extinction, another common occurrence on islands in recent times. And it is exactly this which led to the demise of the Stephens Island wren.

Stephens Island, or takapourewa is located at the northernmost tip of the Marlborough Sounds on the South Island of New Zealand. Up until the 1890s it was free from human impact and pests, and had become the last remaining outpost for the Stephens Island wren.  This changed when it was decided that the island would make a perfect place for a lighthouse. The remoteness and untouched nature of the island is beautifully highlighted by Prof. Richard Holdaway who said that it would have been like stepping back in time. Unfortunately for the little wren species, that moment marked beggining of the end. On such a small island, only 1.84 sq km, there is not much place to hide if you are a bird that can't fly, and especially from a cat. The lighthouse keeper, Lyall (from who the wren gets it's species name) had just that, a cat! According to legend Tibbles the cat made short work of the little wren and has been credited with single pawdedly wiping out an entire species. This of course is not true since the bird was previously found on the mainland. There is an historical account of what did happen on the wiki page.

One last thought I will leave you with is this question; if Stephens Island is 3.4km away from the mainland and the Stephens Island wren was flightless, how did it get there?