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

Since the early 1980s, the numbers of Cuckoos has been in decline and this may be because the populations of some key host species, such as Dunnock and Meadow Pipit, have also declined. Consequently, the Cuckoo is now red list species.

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.

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.