The European Cuckoo - Cuculus canorus -  is one of the UK's fastest declining migrants. Over 50% of the birds migrating between Europe and Africa have disappeared over the past 25 years. Our knowledge about what this amazing species does once it leaves the UK in August is extremely poor, hampering our ability to explain population changes. We lack even basic information about the routes they take to Africa, when they arrive in their wintering grounds, the habitats they use and how they move around within Africa. This information is urgently needed to form conservation strategies and initiate action.

In an exciting new project we (BTO) are tracking 5 Cuckoos on their
migration from the UK to Africa. Already, they are yielding some
stunning results and some totally new information.

Two birds are currently in transit across the Sahara.

We last saw Clement the Cuckoo two days ago in northern Algeria in
what was probably the last bush before the start of the Sahara desert
(see his blog on the BTO website). Today at approx 10:30 GMT Clement
was crossing the Sahara and exited Algeria and crossed into
Mauritania. By 1615 which was the last fix we received today he was
well into Mauritania.

Kasper, our second Cuckoo in Africa travelled 2,200 km in the last two
days and is well into Algeria. He chose what is probably one of the
longest desert crossings in West Africa and when we last heard from
him was two-thirds of the way across and heading for Niger. We should
hear from him later on in the weekend and find out if he made it.

The other three Cuckoos are still in Europe. Two are in northern Italy
having taking a south-eastern route from the UK (as did Kasper).
Clement (named after BTO's director) wasn't one to follow the crowd
and did something we didn't expect and after following the others to
the foothills of the Alps, instead of heading eastwards into Italy,
jinked westwards and entered Africa via Spain. He is keeping up this
SW movement and is now in Mauritania.

The last Cuckoo, Lyster, is still in the UK. We thought birds would
leave around now (mid-late July) so it is a real surprise that he is
the only one left! Dave Leech (BTO), who has an intensive project on
Reed Warblers reported a new Cuckoo egg in a nest this week, so there
are still a few opportunities for Cuckoos left... Not for much longer
we suspect as the breeding season in Britain is virtually over.

The cuckoos can be followed at http://www.bto.org/cuckoos. Maps are
updated automatically at 10:00 GMT each day.

If you can, please try to support the project by sponsoring a Cuckoo.
Satellite tagging is a *really* expensive business (one tag and data
charges for a year are in the order of $4000 per tag) and the public's
support is crucial to us being able to carry on with tracking studies
like this. Tracking provides incredibly useful and unique information
about timings of migration, habitat use outside the breeding season
and will help us work out why 65% of Cuckoos have declined in the UK
over the past 25 years. For your sponsorship you will receive regular
updates as to their progress and you will also support a project that
is producing some ground breaking information. If you are unable to
support us then that is fine, just enjoy the spectacle of the birds'
migration! It is hard not to be moved by these birds and even the most
hard core scientists at BTO are in total awe of what these Cuckoos are
doing.