Giant bird-eating dragonflies cross the Atlantic

GIANT AMERICAN dragonflies have flown the Atlantic.

Their unprecedented arrival in the Isles of Scilly and south-west England is sending waves of excitement through the ranks of British naturalists.

The insects have been identified as common green darners, Anax junius, which occur commonly from Alaska in the far north to Panama in Central America but which, until this month, had never been recorded in Europe.

It is believed these jumbo jets of the insect world - measuring more than three inches long with a wingspan of more than four inches - have been blown off course to Britain while migrating south for the winter.

Their arrival coincides with a spate of sightings of American birds, and follows a weather pattern involving depressions tracking across the Atlantic.

One, a male with a distinctive green thorax, has been present for a week at Penlee Point Nature Reserve, near Rame, south-east Cornwall, and up to six have been reported on the Scillies, west of Land's End, including four together on St Agnes, the most southerly of the main group of islands.

Steve Dudley of the British Dragonfly Society, who is writing a book on dragonflies and has seen one of the green darners, said: "There is no doubt about its identification. Lots of entomologists have now seen it and are equally satisfied."

Green darners are predatory, their diet including wasps, moths, butterflies, beetles, flies and smaller dragonflies. Attacks on hummingbirds, some varieties of which are smaller than they are, have been recorded.

Dr Mark Telfer, of the Biological Records Centre of the Institute of Terrestrial Ecology, near Wareham in Dorset, said that there had been reports of unusually large numbers of the insect on the east coast of North America this autumn so there was a chance more would appear with strong westerly winds continuing.

"It is quite possible for such long-distance migrants to cross the Atlantic unaided in such conditions," he added.

"If sufficient arrive there has to be a possibility a breeding population could become established, although this would be complicated by their need to migrate south to a warmer climate for the winter."

The future arrival of green darners was forecast only in January in a paper by Adrian Parr, published in the entomology journal Atropos.

In it he wrote: "Sporadic appearances do seem highly likely. As with birds, several of the more mobile species [of dragonflies] appear to use the east American coast as a flyway and many have a flight pattern extending into September or October, so that they are potentially on the wing at the start of the period of autumn transatlantic winds."