Summer's over for Clement the cuckoo as he is tracked in Africa

You might think summer has hardly begun, but for Clement the British cuckoo, it's so over that he's already in Africa, the continent where he winters.

Click HERE to view graphic (117k jpg)

Clement is the first of five cuckoos being tracked on their return migration by the British Trust for Ornithology (BTO), and featured in The Independent last week, to leave Europe behind.

Two days ago he crossed over the Mediterranean from south-eastern Spain to Algeria, and is now resting on the northern slopes of the Atlas mountains before the toughest part of his journey – crossing the Sahara desert.

With his fellow cuckoos Martin, Lyster, Kasper and Chris, all caught in East Anglia in May and fitted with ultra-light satellite tracking devices, Clement is part of a fascinating experiment which hopes to solve the last of the cuckoo's mysteries – where exactly the birds go in winter. Their progress can be followed in detail on their blogs on the BTO website, which are constantly updated.

The work is considered vital, because the cuckoo, whose call is one of the best-loved signals of springtime, is rapidly declining in Britain, having tumbled in numbers by 65 per cent between 1984 and 2009.

The birds may be disappearing because of a decline in their insect food in Britain, but it is also possible that they are running into difficulties on their African wintering grounds, or on the various intermediate "staging posts" they use to refuel on their 3,000-mile journeys. Habitat destruction could be to blame.

If this is the case, only a real knowledge of where they actually go when they leave Britain would allow action to be taken to put things right. And that knowledge is now accumulating rapidly – although some of it is unexpected.

Clement has doubly surprised the BTO researchers, firstly because of how early he actually left Britain. He departed our shores on 3 June, a full month before ornithologists previously thought cuckoos began their return migration. The second surprise has been his route to Africa. For while three of his colleagues, Martin, Kasper and Chris, are taking an easterly route, flying down the length of Italy – the direction in which ornithologists have always thought cuckoos went – Clement suddenly switched.

After flying to southern France and spending some time in the Toulon region, leading the BTO researchers to think he, too, would head into Italy, in the first week of July he suddenly set off south-west and flew down the coast of Spain, before crossing to Algeria and the African continent.

The satellite photo shows that his current location, a scrub-covered northern slope of the Atlas mountains in the Sidi-bel-Abbes region, is the very last vegetated area before the vast sandy and rocky expanses of the Sahara, the immense barrier which he will probably cross at night to escape the searing heat and lack of food.

While Martin, Kasper and Chris are solidly ensconced in Italy, Lyster, the last cuckoo, is still in England, somewhere near the village of Reedham in the Norfolk Broads.

Click HERE to follow the cuckoos' journeys