Chris Packham cuckoo believed to have died

Chris is the only cuckoo to have provided scientists with three years worth of tracking data

A cuckoo that provided more data about the birds' migratory patterns than any other has most likely taken his final journey, conservationists have said.

Scientists from Norfolk-based British Trust for Ornithology (BTO) had been following Chris the cuckoo since satellite-tagging him in 2011.

However, the bird, named after wildlife presenter Chris Packham, was reported "missing in action" last month.

The bird had most likely "perished in the Sahara Desert", the BTO said.

It was part of a project aimed at tracking the species' migration, set up in an attempt to determine why the cuckoo population has declined by 65% in the last 25 years.

Chris, represented in purple outlined with blue, already had a weak signal over northern Italy

The bird was one of 16 being tracked as they made the annual 5,000-mile journey south to Africa for the winter.

However, five-year-old Chris had been the only one to have consistently provided UK scientists with migration data since being fitted with his solar-powered satellite-tracking tag.

'No longer alive'

Chris Packham said the bird's data was "vital" in helping to understand the cuckoos' decline.

It left its Suffolk nesting site on 4 July but poor communication in August from its tag led to concern about its fate.

The tiny GPS trackers worn by the birds weigh just 5g

"It is pretty clear now that Chris the Cuckoo... is no longer alive, having succumbed in the desert areas of northern Chad," a BTO spokesman said.

"Cuckoos have faired badly this year due to a cold and wet UK summer.

"Chris therefore started his migration in less than ideal fitness and would have then encountered very challenging drought conditions in Italy on his way to Africa.

"It's therefore not surprising that he perished in the middle of the Sahara Desert."