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Friday, January 19, 2007


Extinction of species is as natural a part of evolution as is speciation. The process of Darwinian natural selection may generate species which are highly adapted to a particular prevailing set of environmental circumstances. The posh name for "highly adapted" is stenoecious. The problem with these highly adapted species is that they "paint themselves into a corner", and if the environmental circumstances happen to change, they are stuffed (Ooops, I mean unable to cope with the changing circumstances). So "adapted" is the opposite of "adaptable" (for those who want to know, "adaptable" species are euryoecious).

My favourite example of a stenoecious species is the Everglade Snail Kite, a critically endangered species, which I have been fortunate enough to see in the Everglades National Park in Florida.

The Everglades Snail Kite - adapted to eat only aquatic snails

This bird is so highly specialised that its bill is critically structured only to winkle out the flesh of an aquatic snail called the Apple Snail. It is superb above all others in locating, catching and eating Apple Snails.

The aquatic Apple Snail - exclusive diet of the Snail Kite

So, from a conservation point of view, if the authorities in Florida wish to increase the flow of drinking water to Miami; or divert the flow of the Shark River into agriculture; or manage some of the Everglades in the interests of the Seminole Indian Tribe, then this destroys the habitat of the Apple Snail. The Snail Kite, whose bill is adapted to dealing exclusively with a diet of Apple Snails, suffers a knock-on in the food chain. If the snail becomes extinct, the kite inevitably follows.

The concern that conservationists feel now is the rate of extinctions . Research reveals that until the 18th century, an average of about 0.25 species became extinct per year. This rate jumped to one species per year in the 19th century, to 1,000 species per year in 1975, and to 40,000 species per year by around the year 2000.

So what has caused this alarming increase in the rate of extinction of species in recent decades? It would be perverse indeed to imagine that man's activities had nothing to do with it. Extinction can be caused by direct hunting: the Dodo, Passenger Pigeon and Stella's Sea Cow are well-known examples.

The Dodo - too nutritious for its own good?

Indirect human affects such as habitat destruction (e.g. tropical rain forests), wetland drainage, pollution and climate change have all taken their toll. However, one of the most important causes of extinction is the most catastrophic, and also the most pitiful because it could have been avoided with foresight. And that is: the introduction of alien species.

In a balanced ecosystem, the eponymous "balance of nature" is in harmony of sorts. There is a complex interacting dependency that maintains a long-term stability. Species become extinct as circumstances change naturally, to be replaced by others that evolve to capitalise on the new situation. But to introduce an alien from a different ecosystem can cause chaos. The places where these affects are most devastating are island archipelagos which became geologically separated early in evolutionary history: Australia, New Zealand, Hawaii and the Galapagos are classical examples.

Australia separated by plate tectonic movement from the super-continent of Gondwanaland many centuries ago. At the time, mammals were at an early stage of evolution, and a separate line, the marsupials, developed in Australia. They became isolated from the mainstream of mammal evolution where the more advanced and "successful" placentals evolved. When Australia became settled by European people, a few placental rabbits were introduced and they were able to out-compete the endemic herbivores and, axiomatically, "bred like rabbits" and virtually took over the continent. In desperation, European foxes were introduced to control the rabbits. Did that work? Oh no, the foxes turned to predate the indigenous marsupials that were not adapted to avoid such predators. There were many extinctions, and many species, including the Leadbetter's Possum, have become endangered.

Leadbetter's Possum, endangered emblem of Victoria, Australia

In New Zealand the position is arguably even worse. This land-mass separated off from Gondwanaland even before Australia, in a period before any sort of mammal evolutionary line had commenced. In isolation, the higher animals in New Zealand were restricted to birds, reptiles, fish and amphibia; but no mammals. (Seals and bats found their way independently in due course). Without the need to escape from mammalian predators, many endemic bird species in New Zealand became flightless, or developed greatly weakened flight. Obviously, the Kiwi is the best known example, however there are dozens of other examples.

As in the case of Australia, the introduction of a few rabbits into New Zealand wreaked havoc. And the response to attempt to control the rabbits? Introduce cats, ferrets, weasels and stoats! The rest, as they say, is history. These advanced mammalian predators ignored the rabbits and took readily to the flightless or weakly-flying bird species. One of the alleged fastest extinctions on record occurred when the lighthouse keeper on Stephen's Island let his cat out, which cleaned up the entire population of the unique Stephen's Island Wren in a couple of hours!

I count myself fortunate to have lived in New Zealand during the 1970s. As a birdwatcher, I was astonished at how much the bird life was dominated by introduced species; the European Blackbird, Yellowhammer, Redpoll, Skylark, the Indian Mynah, to name but a few. To see the interesting endemics required excursions into the thickest parts of the forested National Parks, or even to the off-lying islands where the Wildlife Service had eradicated alien predators. High on my list to see was, of course, the Kiwi, and I was able to locate a few of these as they pecked about on the high-tide mark on a beach at night on Stewart Island.

Flightless Spotted Kiwi of New Zealand

Another rare endemic bird that fascinated me was the Kokako. This had two sub-species inhibiting the North and South Islands, respectively. The North Island sub-species was rare but secure, but the South Island race was precarious. And it was sad to learn from Ju's Little Sister that it has recently been declared extinct.

The North Island Kokako is a shy, secretive weakly flying forest dwelling species. To see one simply "flying about" is extremely unlikely. But there are more subtle methods: being territorial, the males respond very well to tape recordings of the song of their own species. Males regard the recording as a rival intruder and will sometimes emerge to see him off!

And so it was with a tape-recording of a Kokako supplied by the New Zealand Wildlife Service, and a tape player system that would look cumbersome by today's standards, I set off to camp by the shores of Lake Okataina (not far from Rotorua) in the heart of Kokako country. I set my alarm for an hour before first light, and enthusiastically drove to a likely looking spot in the forest and started playing the tape at dawn. You can imagine my excitement when I heard a bird singing the mellifluous fluty notes in response! I remember tingles down my spine, and the hairs standing up on the back of my neck!

But would the bird come out and show itself? No way! By the time the rising sun was casting shadows, the birds had shut up shop and were refusing to play!

The second morning, it was harder to get out of my warm sleeping bag - there were ground frosts even in spring. However, I returned to the same spot, and started playing the tape again and sure enough, the local male responded! Surely, I felt, he would show himself today! And just as I sensed he was getting close, the song from my recorder started deepening in tone, and slowing down. Damn! The batteries were flat! I gave up and went straight to the nearest service station for a new set of batteries!

On the third and final morning, I was suffering from severe sleep deprivation. As the alarm dragged me from the depths of slumber, and the sweetest of dreams, I tried every trick in the book to persuade myself that there was no point; I thought of every excuse why it was futile to try, why I needed another hour's sleep (at least!). But operating on automatic pilot, I dragged myself from the comfort of the sleeping bag and made my way again to the now familiar spot. Would it work this time? Well, yes it did. It was not the best view I have ever had of a bird, I must admit. But it did show itself, briefly, as it hopped along a leafless branch, and then dropped back into the canopy and disappeard from sight. There it was - the Kokako!

New Zealand North Island Kokako - rare, but thankfully well protected


Blogger Kiwi Nomad 2006 said...

You have truly done a Kiwi heart proud with this posting. Sad to say though, extinction and endangered are words that go together far too well with our native birds.

11:23 pm  
Blogger simon said...

Jim- you have outdone yourself on this post. thanks!

I learn a lot. Is it possible that you might be able to do a post along the lines of your lecture at the cumberland bird observers club?

1:36 am  
Blogger Maalie said...

Thanks Kiwi and Simon. I actually put up something about my Marsh Tit Research over a year ago, but sure, I can develop this.

5:51 am  
Blogger Maalie said...

That's enough, Estelle, or I'll have you in the stocks. This is supposed to be a serious post...

4:11 pm  
Blogger simon said...

I agree. there is nothing at all humourous in what he holds in his hands.....

4:24 am  
Blogger Kiwi Nomad 2006 said...

You actually have an endangered opossum in Oz? With my Kiwi experience of possums I thought that they were just about indestructible.

6:41 am  
Blogger TCA said...

What's this the first installment of your memoirs or the first on a series of essays on evolution?


8:41 am  
Anonymous Ann said...

Really fascinating posting. Enjoyed it enormously. Thanks.

10:00 am  
Anonymous Ellee said...

Gosh, I've learnt a lot here, that kokao is fabulous, wish I could see one.

Those extinction figures are dreadful, I would like to hear more about those species.

10:26 am  
Anonymous Ellee said...

P.S. I think Estelle is a bit of a tease ...

10:27 am  
Blogger Maalie said...

Kiwi, yes there are 20 or so possum species in Australia, some very common, some endangered. The possum in New Zealand is the Common Brushtail Possum Trichosurus vulpecula which was introduced to New Zealand from Australia by Europeans to establish a fur industry and this is another excellent example of how an introduced alien has wrought ecological disaster. See more here .

TCA: I did it in response to Ju's Little Sister's request.

Ellee, the vast majority of those 40,000 are invertebrate and plant species lost due to large scale destruction of rain forests, coral reefs, etc., and is of course an estimate. However we are also losing higher animals too, the Yangtze River Dolphin and the South Island Kokako are just a couple that I've heard declared extinct in the last few weeks.

4:06 pm  
Blogger lorenzothellama said...

Trust Estelle to bring the tone down. Well done.
I thought this was really interesting and learned loads. I never knew for example that there were no indigenous mammels in New Zealand. You also reminded me about the hedgehogs, was it in Skye? Someone brought two to keep the slugs down in his greenhouse, but they escaped, and not having any foxes on the island to keep numbers down, they bred themselves witless, until some kind ecologist came and shipped them back to the mainland, so they could be eaten by foxes.

5:17 pm  
Blogger Maalie said...

Nearly right, it was North Ronaldsay in the Orkneys. The hedgehogs multiplied and started taking a fancy to Arctic Tern eggs! In fact I got a research grant to pay for two students to go to study the problem.

5:33 pm  
Blogger simon said...

there are quite a few different possum species.

the problem you have in NZ typifies the problem of introduced species.. eg cane toads here.....

11:35 pm  
Blogger TCA said...

An excellent posting. I was in Rotorua just the other week and I think they still sell those tape recorders.

I met an interesting fellow in the Coromandel at Christmas and he said whilst the Australians are to blame for introducing possums to NZ he actually blamed the Brits for introducing Aussie's in the first place.


5:56 am  
Blogger Kiwi Nomad 2006 said...

lololol tca I love that comment! (But I am not sure simon will!!!)

7:31 am  
Blogger simon said...

sadly i do not... apples do not fall far from the tree and New Zealand is really just another state of Aus (rather like Tasmania).....

and I think the NZ prime minister was a man prior to gender re-assignment (oops Am I being MORE than runcible??) ;o)

10:39 am  
Blogger Davy said...

A lovely bit of work... except that I thought the reason behind most mass-extinctions these days was from the introduction of 30 foot wide commercial machinery, but then maybe I am biased.

Great News! I have the all clear to resume duties in the Corncrake Conservation Project on Monday Next.

12:00 pm  
Blogger Maalie said...

Nice to see you here Billibob!

And you Davy, good luck with the crakes. Room for me for a few days in July?

4:27 pm  
Blogger lorenzothellama said...

Are Aquatic Apple Snails found anywhere else but Florida?

5:04 pm  
Blogger Tortoiseshell said...

Doesn't Kiwi taste like chicken?

5:29 pm  
Blogger Tortoiseshell said...

P.S. Oh bugger - I can see off my tracker that someone has googled "Claire Fallon" and hit my love story! Better fly that disclaimer they do in the movies about fictitious characters etc...

5:35 pm  
Blogger Maalie said...

Lorenzo, yes they are found widely in the tropics and indeed are a pest in some places. But not always in suitable places for the kite which needs very large isolated areas. Popular in aquaria on account of their varied colour. See more here

Tortoiseshell, don't know about that, but the indigenous peoples used to eat them, the bones and remains have been found in ancient middens.

5:40 pm  
Blogger Maalie said...

Tortoiseshell, I wouldn't worry: if you google "Jim Fowler" the first few strikes come up with a well-known wildlife TV presenter in America! There's bound to be loads of Claire Fallons in the world!

5:43 pm  
Blogger lorenzothellama said...

Is it feasible to transport a few Kites to the places where Apple Snails are plentiful that is suitable for Kites? I don't know much about transportation of birds, but Red Kites did rehabit mid-Wales after being introduced there.

6:07 pm  
Blogger Maalie said...

Lorenzo, a good question. In principle, I suppose so, but bearing in mind the disasters of other introductions, it would have to be a last desperate resort (the apple snail itself has become a pest in places where they have been released from aquaria). Re-introductions are normally contemplated only where the cause of extinction is known, and subsequently eradicated. Works well in NZ when you can reintroduce a species on islands when the cats/rats/goats have been got rid of.
As a matter of fact, it was Wales that the Red Kites hung on (but down to 2-4 pairs after the war) and they have increased due to rigorous protection. It is into England and Scotland (where they used to be before persecution) that they have been introduced.

6:46 pm  
Blogger lorenzothellama said...

And are they thriving in the places where they have been introduced?
Off to see Corrie and Eastenders.

7:41 pm  
Blogger Maalie said...

Yes, phenomenally well! They are opportunistic scavengers (they used to keep London "clean" before sewers and dustbins were invented) and given protection from pesticides and gamekeepers they take off like a rocket!

8:21 pm  
Blogger lorenzothellama said...

Well that's good to hear. Maybe the humble sparrow will make a comeback, although we do seem to still have them here. I saw a starling yesterday, the first for ages.

Corrie and Eastenders are very exciting at the moment. Murders in both of them. The Archers are a bit of a pain though and I think I shall boycot them for a while.

11:32 pm  
Blogger Ju's little sister said...

I see I have a lot to catch up on!

opossoms - big pest in NZ not only because they eat all our pohutukawa (see my Christmas post in libramentum if you'd like piccies) but also because they carry TB, which is then picked up by deer and cattle and potentially people too. I know a couple of kiwis who got themselves into a lot of trouble in oz because they teased and threw possums when they are endangered.

Estelle - I laughed!

Simon - aussie was the penal colony, not nz. Enough said.
Also, our trans-gender politician is a woman by the name of Gorgina Beyers and she is one of our more respected government officials. Leave poor old Uncle Helen alone - can't be easy having the nation suspect your husband is gay...

Lorenzo the llama - we have sparrows up to the eyeballs and starlings are a pest. More of that introduced species thingy.

Last, and best of all, Maalie - thank you for your post. I enjoyed every moment of it, you have outdone yourself and I am most thankful. I am impressed with your early mornings whilst on the hunt!

3:49 am  
Blogger Maalie said...

Ju's Little Sister: Thanks! I've been waiting for you before moving on!
I didn't know about the TB though - just another good reason for avoiding introductions.
And we have a "sparrow crisis" in urban areas over here, they are virtually extinct in London now (only 8 (that's 08) in the last count!

7:46 am  
Blogger Ju's little sister said...

I suppose you remember that the NZ Black Robin dropped to 6 TOTAL in existance - the rarest bird in the world. Thanks to Blue and Yellow (named after their rings) and some bush wrens (correct me there if I'm wrong) and most importantly the amazing efforts of DOC, we have them a little more stablised now!

Thank you for waiting for me Maalie, I've been pretty busy with study and will be until about April this year, so the blogs were pushed to the back burner for a bit...

Only six sparrows in London? I can get at least 10-15 on my front lawn just by throwing some bread out there. Wow.

8:38 am  
Anonymous Plumpy said...


8:38 am  
Blogger Maalie said...

J'sLS: Yes, I have that wonderful book about the Black Robin on Little Mangere in the Chathams - it was given to me as a present by someone who worked on it. I have often used that story as a "case history" in my conservation lectures!

8:42 am  
Blogger simon said...

This comment has been removed by the author.

9:34 am  
Blogger Kiwi Nomad 2006 said...

I am still up at 11.11pm as the Black Caps look like they are about to beat someone finally - England!

10:12 am  
Blogger Kiwi Nomad 2006 said...

Well, well well, that is a tunr-up for the books: Black Caps won!

Maalie, I was reading recently where they have found some mammal fossils down Otago way - causing a bit of a rethink of things. I will try and find the reference again for you.

10:19 am  
Blogger Maalie said...

Thanks, Kiwi, I would be gratefully interested. My guess is that they represented some lowly primitive form that never really took off, and fizzled out. Such is the way of evolution.

4:46 pm  
Blogger Tortoiseshell said...

...are you by any chance referring to the 2003 English rugby World Champions? Or the 2005 Ashes winning England cricket team?

6:29 pm  
Blogger Ju's little sister said...

Tortoiseshell, You know how the English rugby team had the large O2 symbol on their shirts? That represented games played (2) games won (0) against the All Blacks. No kidding, it's true.

Maalie we had a wonderful kiddies book with amazing illustrations at my primary school about the Black Robin, perhaps it's the same one? We also performed a song for our end-of-year break up.

Kiwi Nomad, I'd be interested in that link too!

Simon. Simon. Simon.
You can't get away from it all by making stuff up about surgeons and ships. The police came to your house didn't they? Okay okay just kidding and probably in bad taste too.
My point was that we are not another state of Oz as we were never associated with the convicts. Brits vs. Maori, yeah, what's your point?


6:45 pm  
Blogger Kiwi Nomad 2006 said...

OK I found where I read it. I bought a wonderful book late last year, called "Ghosts of Gondwana: the history of life in New Zealand" by George Gibbs. Pgs 108-109. Not many mammalian fossil bones found but at least two kinds of bats. Thought I read somewhere in the book that there were a few other mammalian bones as well but can't find that now.
The fossil deposit now being examined more closely is from near St Bathan's in Otago. Lots of fish bones. But also teeth from a crocodilian species. And bones from skinks and geckos. Lots of bird bones. A quote for you Maalie: "The songbirds - at least four species - indicate that honey-eaters (birds like tui) were here 15 MYA, which is a much deeper history than had previously been thought by ornithologists." and "Unlike the plants, the birds were not particularly reminiscent of Australian forms, instead indicating a distinctive New Zealand fauna at that time."

This is a wonderful book. Will have to re-read it again!
I am starting a Massey paper on NZ fauna in about a month. When I have access to the online journals again I will see whether I can find out some more about those mammals!

11:22 pm  
Anonymous Ellee said...

Maalie, I woke up to a lovely covering of snow today, I'm sure you have too.

I just want to ask your advice regarding rabbits, we bought one for my son and let it roam the garden in the day, putting it in its hutch at night. Only it doesn't seem keen to run around on the white stuff. Silly question, I know, is it best to leave him indoors today? We actually bring him in and he sits in a box quite happily chomping away. I really regret buying him, he has virtually devoured my entire garden which I recently restored. Being a man of nature, I thought you might understand the habits of rabbits.

8:11 am  
Blogger TCA said...

Can you cook Rabits the same way as Hare? Jugged Hare at Maalie court is recommended. I have a recipe for Rabbit Curry.


9:09 am  
Anonymous Ellee said...

TCA, How cruel you are! Anyway, I decided I can't have a pampered bunny sitting in his hutch all day, so he is out now and finding his way around my snow covered garden, it must be a strange experience for him the first time.

10:01 am  
Blogger Maalie said...

Ellee, yes, I think it is best for your rabbit to learn about life!

Kiwi, thanks for that info.

3:10 pm  
Blogger Kiwi Nomad 2006 said...

maalie... there is an interesting article on the NZ Herald website this morning about how avian malaria might threaten our native birds. It describes how the introduced birds just carry it, but our birds have no immunity as they have not been exposed in their evolution.

6:56 pm  
Blogger Kiwi Nomad 2006 said...

hmmm breaking that link into two lines:
Hope you can see it all now!

6:58 pm  

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