Sudden influx of exotic Mediterranean herons excites birdwatchers

A number of southern Europe's heron species have suddenly arrived in Britain, in an exotic influx which is exciting birdwatchers. Most people know of the widespread grey heron, one of our most familiar birds and also one of our tallest - it stands 3ft high, with a 6ft wingspan (and raids your garden pond). But recently, several of its continental cousins, more typical of Spain and the Mediterranean, have cropped up around the country.

At the top of the rarities list is a squacco heron, a squat but striking buff-coloured marsh bird, which has turned up on the Thames marshes east of London, at the Crossness nature reserve in Abbey Wood. It was last seen in the area in 1866.

A bird with charisma, the squacco heron is the symbol of Spain's national bird protection society. Other examples have recently been seen at Oare Marshes, Kent; Lodmoor reserve at Weymouth, Dorset; the Isles of Scilly and in Co Wexford, Ireland.

A night heron, a similar-sized grey bird with a black crown, which is also a rare visitor to Britain from southern Europe, is present at the moment at Methley on West Yorkshire's river Calder, while several purple herons, nearer our own heron in size but much darker, have been seen across the country, from the Minsmere reserve in Suffolk to Hamptworth in Wiltshire.

Other exotic visitors which are close relatives of the heron family have also been in evidence. Rainham Marshes in Essex is sheltering a spoonbill and more than 40 have been reported this spring, including up to eight at Cley on the north Norfolk coast and five at Middlebere, Dorset.

Last week at Rainham there was also a cattle egret, so named because it associates with livestock to catch small creatures they disturb, while seven great white egrets recently seen included one on the Shetland Isles, two on Humberside, and the rest in Cornwall, Dorset, Gloucestershire and Norfolk.

Most unexpected of all was a report of 14 glossy ibises flying east over Addlestone, Surrey - possibly part of the record flock of 17 that was seen earlier in the spring in Cornwall and Gloucestershire. "At least one or two of these birds turn up regularly most years, but usually not all at the same time or in the sort of numbers experienced this spring," said Mark Grantham, a migration expert at the British Trust for Ornithology.

"It might take a lifetime for many birdwatchers to get round to seeing all the European herons and related species in Britain, but lately virtually the full set have been on show here."

He thought an anticyclone over southern Europe may have influenced the arrival by pushing birds migrating from Africa too far north, but Britain's milder weather, perhaps influenced by climate change, was probably another factor.