British birds are starting to lay their eggs more than a week earlier than usual, probably owing to global warming, experts reported yesterday. Dr Humphrey Crick and colleagues at the National Centre for Ornithology in Thetford studied records going back to 1975. Every year 1,000 volunteer bird-watchers keep a close account of when and where birds lay their eggs. "We found significant trends towards earlier laying dates for 20 species," the researchers wrote in a letter to the science journal Nature. Some species set up house 17 days earlier while some had just moved their dates forward by four days. The average was 8.8 days.
In April, researchers at Boston University said the growing season for plants in the northern hemisphere had moved forward by about a week.
Dr Crick's group said laying eggs a week early could be an advantage for birds if it gave their young more time to grow before winter. But it could be a disadvantage if food supplies, such as plants or insects, were not seeing the same changes. Meanwhile, marine experts have claimed that acoustic alarms attached to fishing nets can prevent porpoises from getting caught and drowning. In a field test of warning devices designed to protect marine mammals, US researchers, writing in Nature, said the devices greatly reduced the number of porpoises caught in fishing nets.
Dr Scott Kraus of the New England Aquarium in Boston and a team of marine scientists said the effect was enormous. "The most serious danger to dolphins and porpoises around the world is the threat from various forms of gillnet fishing." The group added: "More than 80,000 small cetaceans [dolphins, porpoises and small whales] are killed annually in coastal waters around the world, and at least two species are in imminent danger of extinction because of fishing activities." Commercial sink gill-net fishermen from the coasts of New Hampshire and southern Maine took part in the experiment. Some of their nets were equipped with acoustic alarms that sounded as soon as they hit salt water, while others were fitted with devices that looked the same but emitted no sound.
Two porpoises were caught in the nets using the alarms while 25 were caught in nets carrying silent devices. The same number of cod and pollock were caught in nets using either kind of alarm. Herring, the main prey of the porpoises, also seemed to respond to the alarms.
The World Wide Fund For Nature yesterday accused Japan of hampering UN climate change talks in Bonn. Japan is holding up progress by "spreading confusion" about the issue of reducing carbon dioxide emissions and showing lack of commitment to combatting climate change, the WWF charged.
"WWF believes Japan's actions seriously threaten the success of the Climate Change Summit that it will host in Kyoto at the end of the year," it said.