Coral fears

reached so far to the south-east of Africa as Natal, seems to me extraordinary”, wrote Witherby. The primary purpose of bird ringing was to map bird migration, and much information about migration routes and winter and summer destinations has been obtained over the past century. Ringing is still based on the original principles but techniques have been refined and improved. And researchers have shown that many other aspects of bird biology can be informed by ringing. When ringing began, it was known that birds migrated. People had noticed that up to a quarter of species in northern Europe, ranging from the swallow, cuckoo, nightingale and warblers, appeared in the spring and, after breeding, disappeared in the autumn. It was assumed they were going somewhere warmer for the winter but no one knew quite where until the beginning of ringing. And no one had any idea how far swallows travelled until that first ring on John Masefield’s bird was found in Natal. The writer, Michael McCarthy, recounts in a new book Say Goodbye to the Cuckoo the letter Witherby received from the proprietor of the Grand Hotel, Utrecht, Natal. “Dear Sir, On December 23, a swallow was caught in the farmhouse of the farm Roodeyand, 18 miles from this town, with a metal ring around round its leg, with the words Witherby, High Holborn, London and on the other side B830... As I am interested in birds of any sort and the migration of the same, I shall be glad to know if you receive this letter safely.” The revelation was stunning that such a small bird, iconic of the arrival of the northern summer for many cultures, could travel so far. Swallows have been revered for centuries: a picture of a pair in flight has been discovered on a Minoan wall painting found in Santorini, Greece, created almost 4,000 years ago. “At a stroke it was revealed that swallows breeding in the British Isles migrated to winter in South Africa, something even today we find hard to credit,” writes McCarthy. But, while ringing programmes have revealed much about the winter destinations of the swallow, little is still known about the winter locations of swifts and house martins — only two ringed house martins have been recorded — in Senegal and Nigeria. With climate change, ringing programmes can throw new light on bird behaviour. Since the 1970s blackcaps, which normally winter around the Mediterranean, were increasingly wintering in Britain. It was thought that summer visitors were just staying put, but ringing programmes revealed that the winter birds were from continental Europe and had decided to migrate west rather than south and milder winters meant they were able to find sufficient food. Another outcome of ringing programmes has been to reveal the longevity of some birds. A number of seabirds ringed around the coast of Britain have been found alive after 40 years: one manx shearwater ringed as a chick on Bardsey Island in north Wales was recorded 51 years later. And the distances travelled by such birds are staggering: this bird would have spent each winter off the coast of southern Argentina, covering a distance of 1.5 million kilometres in its lifetime. Other revelations from ringing programmes include an Arctic tern ringed in Anglesey, north Wales, in June 1966 that was found dead six months later in New South Wales, Australia, 11,300 miles away. And, in another new book celebrating bird migrations, the travel writer Horatio Clare on seeing the arrival of swallows one spring in south Wales decided to follow their journey from South Africa to the UK. Crossing 14 countries he followed members of the ‘swarm’ of birds he found in Blomfontein that returned to Wales. His book — A Single Swallow: An Epic Journey from South Africa to South Wales — is more romantic than scientific, but celebrates the return of these birds to Europe as the Minoans did millennia ago. More practically, the British Trust for Ornithology (BTO) focus on the population data to be gathered from ringing. “We are interested in demographics: births and deaths... productivity and survival. Collection of this kind of information allows us to look in detail at what is happening to populations. Population declines are often caused by changes in just one part of a bird’s life,” the BTO say, and believe ringing programmes can provide vital insight. There is a growing threat to the socalled coral triangle in south-east Asia — home to 3,000 fish species and 40 per cent of the planet’s most significant marine environment. Pollution and deforestation have already caused significant damage and these and other threats may destroy all the coral reefs by the end of the century according to Ove Hoegh-Guldberg, director of the Centre of Marine Studies at the University of Queensland and lead author in a new Worldwide Fund for Nature (WWF) report*. The coral triangle covers an area the size of the US and is home to more than 35 per cent of coral reef fish and 30 per cent of the world’s corals. “More marine species exist in the coral triangle than are found in all the other tropical oceans put together,” the report says.