Extinction is not always for ever

Extinct Birds
November 30, 2001

When Errol Fuller published the first edition of this book in 1987, Jerdon's courser, an obscure Indian wading bird, had last been seen in 1900. There had been only two earlier sightings, in 1848 and 1871.

Fuller duly pronounced it extinct but, unfortunately for him if not for the species, the report of its demise was exaggerated. At just about the time the first edition was being published, a Jerdon's courser was spotted again.

There is, after all, something rather final about the book's title. Extinction is, according to the cliche, for ever. A second edition, some dozen years later, should, in theory, contain an even longer list of species that have disappeared in the interim.

The story is not as simple as that: Fuller has had to restore a number of "extinctions". Not only Jerdon's courser but the four-coloured flowerpecker, a Philippines endemic also regarded as extinct since 1900, have been reinstated following their rediscovery in the wild. A number of other species regarded as probably extinct in 1987 have also been restored.

The flowerpecker's survival is instructive. Fuller says there was cast-iron evidence that the species had died out with the total deforestation of the island where it lived. In fact, vestiges of forest survived but no one had gone to check on the bird population.

Fuller has included a number of birds whose status is equally problematic. Three North American species - the ivory-billed woodpecker, Eskimo curlew, and Bachman's warbler - have not been recorded for significant periods and most ornithologists regard them as extinct.

Fuller accepts that he may be proved wrong again. The woodpecker, in particular, is notoriously secretive.

So should the eye-catching title perhaps have a qualifying phrase, "or believed to be extinct on the best possible evidence"?

Only in the mind of a pedant. Extinction is the ultimate disaster for a species. The significance is one for humans to assess: extinction is significant for aesthetic, economic or scientific reasons. The near-eradication of certain fish species through over-exploitation may have severe repercussions on communities, and almost any extinction is of scientific significance. What caused the extinction? Was it avoidable? What are the consequences for the environment? All have deeper resonances for humans.

Bird species are frequently highly visible, often aesthetically pleasing. They act as effective indicators of the health of an ecosystem. Their short lifespans and frequently high reproductive rate mean their populations are sensitive to fluctuations, and there are plenty of examples in recent ornithological history of species being forced to the brink of extinction and beyond by environmental pressures.

The disappearance of the dodo, the extinction by human agency of the great auk and the passenger pigeon, are reminders of how easily a species can slip away. Natural selection - an adaptation to a changing environment over time - is one thing; but persecution by human intervention is quite different.

The predictions are worrying. One in eight of all bird species is said to be in danger of extinction in the next century. Of these 1,186 species, 182 have only an estimated 50 per cent chance of surviving over the next ten years, 320 species are classified as endangered and 681 are vulnerable, while an additional 728 are close to qualifying as threatened.

Habitat loss and degradation are the major causes of endangerment in birds. Between 1960 and 1990 some 4.5 million square kilometers, 20 per cent of the world's tropical forest cover, was cleared. Of the 1,186 threatened birds, 99 per cent are at risk from human activities such as agriculture, logging and hunting.

Fuller's reproduction of Victorian or earlier engravings, the taxidermists' specimens and blurry photographs graphically chart the losses to the world's avifauna. A final chapter on mystery birds and hypothetical species sets out an array of ornithological puzzles. It questions ornithology's claim to be an exact science, pointing to the gullibility of some authorities who are convinced by flimsy evidence to accept the one-time existence of a dubious species.

David Jobbins is foreign editor, The THES .

Extinct Birds

Author - Errol Fuller
ISBN - 0 19 850837 9
Publisher - Oxford University Press
Price - £29.50
Pages - 398

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