This is the weather the cuckoo likes and so do I - the famous opening line of the Thomas Hardy poem, Weathers.

It would appear that the recent bout of warm sunny weather appeals to cuckoos who arrived back at Wicken Fen on 14 April - a full five days earlier than usual. Detailed records kept by the Wicken Bird Ringing Club dating back over 35 years point to an average arrival date of 19 April.

The European cuckoo is about the size of a dove and both sexes have bluey-grey backs and heads, with brownish white barred chests. They spend most of the year in Southern Africa returning to Britain in April to breed. Throughout the breeding season male cuckoos can be seen perched prominent in tree tops, its tail cocked and wings drooped calling to attract a mate. A good place to spot cuckoos is from Wicken's Tower Hide overlooking Adventurer's Fen.

Cuckoos are one of a handful of species throughout the world (and the only species in Britain) that are parasitic breeders. They lay their eggs in the nests of another species, leaving all the nurturing to the host species. Individual female cuckoos can only dupe one host species. At Wicken Fen, the hosts are reed warblers, but elsewhere throughout Britain the host species include dunnocks, meadow pipits and pied wagtails.

A female, heavy laden with egg, stakes out the warblers tiny intricate nests from the trees above the reed lined banks of Wicken Lode and ditches where they nest. The moment they leave the nest unguarded she will swoop down lay her egg and remove one warbler egg, the whole process taking as little as 10 seconds. Her egg will mimick the warblers greenish eggs, albeit somewhat larger.

It is perhaps one of nature's great mysteries - why do the warblers incubate an egg clearly much larger than their own - or look after a chick so obviously unlike their own. Once hatched the cuckoo chick has one thing on its mind - murder! Naked and blind it struggles to remove any un-hatched eggs and young warbler chicks from the nest to eliminate competition for food. In only two weeks, the young cuckoo will have virtually outgrown the nest and will already be about three times the size of the adult warbler with an appetite to match.

The last calls of the cuckoo are heard in early July as the adult birds depart after their brief stay for their return journey to Southern Africa. Their young fledglings will remain under the care of the warblers and will eventually head south themselves in August or September -hopefully to return to Wicken Fen next spring.

Ends

Notes to Editors

1. Wicken Fen Nature Reserve and Visitor Centre is open daily (except Christmas Day) from 10am-5pm. Entry is free to National Trust members and under 5's. Adults £5.99, children £2.99, family ticket £14.99 (two adults and up to 3 children)

2. Wicken Fen organises a comprehensive programme of activities and events throughout the year.

3. Wicken Fen was purchased by the National Trust in 1899 -the first nature reserve owned by the Trust.

4. The National Trust is a charity with a love for preserving historic places and spaces across England, Wales and Northern Ireland. In short, we're a conservation charity that protects over 350 historic houses, 160 gardens, 1,100 kilometres of coastline, 254,000 hectares of land of outstanding natural beauty, 6 World Heritage Sites, 28 castles and 60 pubs - and opens them for people like you to enjoy. Find out more at: http://www.nationaltrust.org.uk 

Further Information

To find out more please contact: Howard Cooper, Communications Officer, National Trust Wicken Fen - Tel 01353 720274 Mobile 07826 874133 or e-mail: howard.cooper@nationaltrust.org.uk