They're clocking up thousands of miles (kilometers) as they complete their long journey from England to Africa _ and five migrating cuckoos fitted with tiny tracking devices are providing new information which could help explain a sharp decline in the number of the birds in Britain, scientists said Friday.
The five cuckoos are carrying satellite tags _ which look like miniature backpacks _ fitted before they began their migration from Norfolk, in eastern England, in July bound for Africa's southern nations. Information collected on their route is helping experts learn more about the impact of population growth and climate change on the birds' habitats.
For the first time, scientists are examining where and when the migrating cuckoos stop off on their journey through Africa, hoping to understand more about why fewer and fewer birds are able to make the return trip the following year.
Graham Appleton, a spokesman for the British Trust for Ornithology, which is carrying out the research work, said the number of cuckoos in Britain has fallen by about 60 percent over the last 25 years.
Cuckoos traditionally arrive in Britain in April and migrate again around June or July.
Appleton said that the five birds were captured in large mesh nets _ lured with a recording of a female bubbling call _ and fitted with the 5 gram, solar-powered satellite tags.
"The tags turn on for about 10 hours every two days, and relay information about where a bird is. That will tell us more about the routes the cuckoos take to their wintering areas and where they stop off along the way," he said.
Once they know more about the cuckoos' favored stops, scientists plan to work with colleagues in those countries to examine the possible reasons behind the fall in numbers of migrating birds. "We'll be looking for ways to work with local partners in those areas to look at the impact of population growth on biodiversity and on habitats," Appleton said.
Four of the cuckoos have made swift progress. Two are now in Chad, with other birds in Burkina Faso and Nigeria.
A fifth bird, named Lyster by scientists, remained in Britain until late July, and was tracked on Thursday to the coast of Morocco, about 13 miles (20 kilometers) from Casablanca.
None of the birds have completed their journey yet to the bottom of Africa.
"The satellite tags should last for at least a year, so we also hope to track the birds as they make their return journey to Britain," said Appleton.
British Trust for Ornithology: http://www.bto.org/