Rare birds just can't stand the heat

The toucan, the frog and a host of birds have all fallen victim to the greenhouse gases produced in the name of civilisation. Global warming is playing havoc with the breeding and nesting habits of some of the world's rarest species, causing them to head north or veer south and threatening others with extinction.

The explosive implications of global warming for wildlife across the planet are to be unveiled at a United Nations-sponsored environmental conference being held next week in Japan.

Among the creatures worst hit are:

q the Sooty Shearwater, whose food source has been reduced by warmer oceans;

q the Costa Rican Golden Toad, which has been threatened by a virus related to the stress of global warming;

q Edith's Checker-Spotted Butterfly, which is heading north to find a cooler climate;

q the Keel-Billed Toucan, forced from its natural habitat to higher ground and to the north by rising temperatures.

The Royal Society for the Protection of Birds will present a report, "Climate Change and Wildlife", to the Kyoto convention that will outline a correlation between global warming and changes in the behaviour of plants, and wildlife.

The convention, which begins on 1 December, will focus on European Union proposals to reduce emissions of CO2, the gas most closely associated with global warming, by 15 per cent of 1990 levels by 2010. But the RSPB will call on delegates, including Britain's Deputy Prime Minister, John Prescott, to act promptly to avert the destruction of fragile eco-systems.

One of the species of birds worst hit is the Sooty Shearwater. Ten years ago there were five million Shearwaters off the West Coast of the United States. Today they have declined by almost 90 per cent. "At the same time as their numbers have dropped the temperature of the ocean surface has warmed up," said Barnaby Briggs, the RSPB's energy and transport policy official, who will be presenting the report at Kyoto. "Warmer water has reduced the upwellings in the Pacific which bring the Shearwaters' main source of food, plankton and squid, to the surface."

Another species affected by warmer weather is the Costa Rican Golden Toad which has disappeared and is feared to have become extinct because its natural habitat has been lost. A global virus has hit the population numbers of 40 per cent of frog and toad species across the planet. "This decrease is specifically caused by a virus but we believe the toads are becoming more vulnerable to disease because of the stresses they are facing as a result of climate change," said Mr Briggs.

Closer to home there have been predictions that malarial mosquitoes will soon berth on the shores of southern England, but the effects of global warming on wildlife in the United Kingdom may already be more profound.

"It is a fact that our spring now comes a week earlier and two out of three birds are nesting earlier" said Mr Briggs. "An early spring has a real impact on eco-systems. If oak trees bud earlier and caterpillars pupate earlier but a Great Tit fails to nest ahead of time then the tit's food source - caterpillars - will have disappeared when its chicks eventually hatch."

A similar pattern is also emerging with newts and their main food source, frog spawn. Newts are arriving up to four weeks earlier each year but frog spawn is only hatching two weeks ahead of its traditional time. As a result, newts are dying because their food source is unavailable; this also has a knock-on effect for larger fish and birds that usually prey on newts.

A particular concern for the RSPB is that as temperatures rise, birds and animals are heading north and south away from equatorial regions which have become too hot. "Eventually they will have nowhere to run and many species will not be able to adapt," said Mr Briggs.

One creature forced to move north to find a more suitable climate is Edith's Checker-Spotted Butterfly which is found in the west of the US. It has moved to a band of land whose upper and lower limits are some 92 kilometres north and 124 metres higher than its traditional habitat. In Europe, nine out of 14 species of butterfly observed in similar exercises, have moved north by around 200 kilometres.

This shift is consistent with rising temperatures, says Mr Briggs. "For every 0.7C increase in temperature, you will find that the climate that previously existed in one place is now found 105 kilometres north and 105 metres higher" he said.

In Costa Rica, the Keel-Billed Toucan and the Blue-Crowned Motmot, a relative of the Kingfisher found in deep forests, have both been forced to move to higher ground to find comfortable conditions. "These creatures live in the cloud base of forests and that cloud base has risen in the past few years," said Mr Briggs.

"We have no definite proof of a link between climate change and the behaviour we are seeing in birds and animals but in a court of law you would call our findings circumstantial evidence" he said. "To say these events are not related is stretching coincidence a long way.

"It is not just important from an aesthetic point of view if wildlife, trees and plants die out. This has implications for humans because millions and millions of people depend on wildlife and plants."