Ornithology: A love affair (Ockham's Razor)

To: "Canberra Birds" <>
Subject: Ornithology: A love affair (Ockham's Razor)
From: "Tony Lawson" <>
Date: Wed, 9 Feb 2011 22:25:11 +1100
Ornithology: A love affair
Sue Taylor takes us on a journey of discovery and enlightenment, introducing us to all her feathered friends.

Robyn Williams: Birds. Well my own encounters with birds on the weekend were a total of eleven on the deck in the country, including some belligerent lorikeets shoving every other bird including big cockatoos out of the way to get at the seed. And on the beach, a sea eagle having lunch. It took very little notice of me, just a casual glance, and then continued chomping at its carcase.

Sue Taylor has scored over 700 twitches by contrast, and regular listeners to this program will know the lengths she goes to to see more. Sue.

Sue Taylor: Someone wrote a book recently called One Hundred Birds to See Before You Die. I thought it was an interesting concept and started wondering what birds I simply had to see in my lifetime. Ask any Australian birder which bird they'd most like to see, and they'll probably say a night parrot. Perhaps the more audacious amongst us might say a paradise parrot - a bird called rare when I was a child and now sadly extinct. Outside our continent I've always wanted to see a flamingo in the wild, and a scarlet ibis and a roseate spoonbill. (Strange that they're all pink and pink is my least favourite colour). I'd also rather like to see some hummingbirds hovering in front of colourful flowers. I've also always yearned to see a roadrunner. I don't know why - perhaps it's because the cartoon representation is so cheeky, and I like the caprice of a bird that can out-think a coyote.

These are all fanciful whims - I don't really expect to see flamingos or hummingbirds any time soon. Or night parrots for that matter.

But one bird I have always been determined to see simply because it looks so stunningly beautiful in the bird books is the black stilt.

We have black-winged stilts in Australia. They are sometimes called pied stilts, or white-headed stilts and they're not only in Australia, they're cosmopolitan. They are smart black and white birds with long pink legs and a long straight black bill. A medium-sized wader, a bit smaller than a silver gull, they are pretty enough birds, taken for granted perhaps because they're so common and widespread.

Black stilts, on the other hand, are found only in the Mackenzie Basin on the South Island of New Zealand. The Maori call them kaki and they are described as 'the world's rarest wader'. They are most elegant birds. Like our black-winged stilts, they have long pink legs and a long black bill. But their plumage is entirely black.

So when we planned a trip to New Zealand recently, I was eager to see a kiwi of course, and I wanted to see wrybill - the only bird in the world with a bill bent to the side - but the bird I planned the trip around was the black stilt. I knew they were endangered and had a very restricted range. But until I embarked on my trip preparation and pre-reading I hadn't appreciated just how rare they are.

Volume 2 of the Handbook of Australian, New Zealand and Antarctic Birds published in 1993 informed me that there were fewer than 50 birds. My New Zealand field guide, Heather and Robertson, published in 200-5, stated that there were about 160 birds in 2004 - 72 in the wild and 47 in captivity at Twizel, which adds up to 119, not 160. Where the other 40 birds are is not stated. They might be juveniles or in captivity elsewhere there is a small number in captivity in Christchurch. Anyway, I thought that perhaps things were looking up for the black stilt - an increase from fewer than 50 to about 160 in a decade seemed positive progress to me.

I started by booking a tour of the Black Stilt Recovery Centre, near Twizel in the spectacular Southern Alps, about 60 kilometres south of Aoraki Mount Cook.

The Black Stilt Recovery Centre is run by the Department of Conservation and guided tours are conducted by enthusiastic and knowledgeable volunteers - at least ours was.

We were given an introductory talk, then shown some captive birds - and they were just as breathtakingly beautiful as their photos in my bird books. I learnt that in the 1970s the population was reduced to 23 adult birds. In August 2009 there were 181 birds in the wild - 94 adults and 87 immature birds. Of all the birds in the wild today, only one was not bred in captivity.

We were given a moment to ponder the implications of that, then we were taken into a room crammed full of posters, photos, graphs, a live-time camera on unhatched eggs in an incubator and several stuffed examples of stilt predators. In Australia, we're familiar with the problems of cats and rats. New Zealand also has weasels, ferrets, stoats and (would you believe?) hedgehogs that eat stilts' eggs and our own beloved possums, introduced so New Zealand could develop a fur trade. On one wall a table showed the numbers of animals caught in traps in the Tasman delta in the year to September 2009. The total is an amazing 1,435, comprising mainly hedgehogs, stoats and cats. Since March 2005, they have caught a phenomenal 6,261 animals. More worryingly, in the last year 39 animals were caught at the Black Stilt Recovery Centre inside the predator-proof fence. These were mainly stoats and rabbit but there were also weasels and mice and one cat and one ferret. The Department of Conservation regards this as 'a trickle of predators' and concludes that 'the predator proof fence continues to act as a barrier against invasion' (!) I'd have to say that if 39 animals were caught in one year, the fence is not a barrier against invasion at all. And if a cat can penetrate the fence, I'd be checking the fence thoroughly before setting more traps.

Having admired the posters on the wall and the various artefacts, we were shown a video with a brief history of the Centre and its work. Then we were taken to the bird hide where we could look down on the three large aviaries where the chicks are raised

Eggs are laid by captive birds and are also gathered from the wild and placed in an incubator. The birds immediately lay again and the eggs are again harvested. The usual clutch size is four, and the birds produce up to four clutches each season, so with wild and captive birds, the Recovery Centre regularly raises 100 chicks to fledgling age. When they are judged to be old enough to fend for themselves, the juvenile birds are released into the wild.

The long-term objective of the project is that the wild population will be sustainable and there will no longer be the need to release captive bred birds.

The Centre is having commendable success in hatching eggs and rearing chicks. Where their success is not so commendable is the survival rate of released birds.

My pre-holiday reading informed me that the birds suffered from habitat loss and predation, and that the hydro-power development in their last remaining stronghold was believed to be a fatal blow that the reduced population could not withstand. Hence the establishment of the Black Stilt Recovery Centre. Conservationists like to blame developers and it's undeniably true that the birds would have had more habitat had the hydro development not occurred. Creating dams destroys the braided rivers where the black stilts breed. But it seems to me that the problem lies not with habitat loss at all but with introduced predators. Introduced weeds provide cover for predators to approach ground nesting birds, but it is the predators that kill the birds, not the weeds. It would be good to eradicate all the weeds, but wouldn't it be wonderful to exterminate all the introduced predators.

There is, however, another environmental problem confronting these birds. It is an invasive freshwater microscope alga, introduced to New Zealand on the felt booties of fly fishermen. It is called didymo or, more graphically, rock snot. It forms a thick brown layer on the bottom of streams, smothering everything - rocks, plants and insects, small molluscs and small fish that black stilt eat.

I have a healthy scepticism about captive breeding programs. I don't know of many that could be classified as an unqualified success.

And the Lord Howe woodhen would be one, where the captive breeding program has brought the birds back from the brink of extinction with a now stable population of 200 birds. The black-eared miner would be another. Ornithologists successfully relocated these birds n the wild - an impressive achievement for birds that next colonially.

The two local captive breeding programs of which I'm aware have not been quite so successful. Enormous effort has gone into breeding our handsome orange-bellied parrot - a brave little bird that nets in southern Tasmania in summer and crosses Bass Strait to winter on the mainland To the best of my knowledge the populating of orange-bellied parrots has not increased despite decades of dedicated work. I suppose the fact that the population has not decreased is a credit to the program. The other captive breeding program of doubtful success is Victoria's avifaunal emblem - the helmeted honeyeater. This bird is a gorgeous gold and black Victorian icon which has not responded to years of work and funding. It is, when all is said and done, just a race of the only slightly less stunning yellow-tufted honeyeater. Many conservationists ask should limited funding be allocated to a race of a species that is common? This thinking has led to the unfortunate nickname of the helmeted moneyeater.

In New Zealand I encountered conservationists asking the same question. It is apparent that the Department of Conservation has devoted significant resources to the black stilt recovery project. As the black stilt hybridises with the black-winged stilt, people question whether it is a species at all. One of my older bird books states authoritatively that the black stilt is a face of the black-winged stilt. Current scientific orthodoxy classifies the black stilt as a species, and our guide informed us that DNA tests confirm this status. The Black Stilt Recovery Centre admits that hybridisation is a problem and even confesses to human culling of hybrids.

I do know that some scientists openly espouse the theory that races should be proclaimed species, if it will assist arguments for research funds. Heaven forbid that I should suggest such a thing in the case of the black stilt - I have no evidence for that whatsoever.

New Zealand is achieving impressive results with reintroduction of endangered species to predator-free islands. Kakapos have been successfully introduced to Codfish Island. Both the New Zealand robin and the saddleback have been introduced to Ulva Island and the short plover, another rare wader, is being translocated to Mana Island.

One of New Zealand's best success stories is the eradication of rats from Campbell Island. This is a big island, 11,000 hectares, and it was an expensive undertaking. However, it was superbly successful. The intention was to reintroduce the Campbell Island pipit and the world's rarest duck, the flightless Campbell Island teal. But, as soon as the rates were gone, the birds didn't wait to be reintroduced. They moved in themselves voluntarily.

The team which did such good work on Campbell Island is now being asked to assist with rabbit and rodent eradication our own Macquarie Island.

I think the New Zealand Department of Conservation is to be congratulated for its ground-breaking work. I applaud what is being done at the Black Stilt Recovery Centre. And I'm delighted that I saw black stilts in the wild, not just imprisoned in aviaries. I saw three - a pair on the Tasman delta a little north of Twizel, and another bird the next day some kilometres to the south. They are such beautiful birds, I hope they will always be there for people to see.

And now for the night parrot ...

Robyn Williams: Good luck. And if she spots one, we'll let you know. And so will the newspapers, no doubt. Sue Taylor in Melbourne. And this week, while the cyclone smashed Northern Queensland one wonders where the birds went.

This is the email announcement and discussion list of the Canberra 
Ornithologists Group.
Please ensure that emails posted to the list are less than 100 kb in size.
When subscribing or unsubscribing, please insert the word 'Subscribe' or 
'Unsubscribe', as applicable, in the email's subject line.
List-Post: <>
List-Help: <>
List-Unsubscribe: <>
List-Subscribe: <>
List archive: <>
List manager: David McDonald, email 

<Prev in Thread] Current Thread [Next in Thread>
  • Ornithology: A love affair (Ockham's Razor), Tony Lawson <=

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the Canberra Ornithologists Group mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the list contact David McDonald, list manager, phone (02) 6231 8904 or email . If you can not contact David McDonald e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU