Norfolk hawker

Norfolk hawker by Malcolm FarrowNorfolk hawker by Malcolm Farrow

Aeshna isosceles

The Norfolk hawker is a splendid dragonfly of early summer. A striking tan-brown with green eyes and clear wings, a well defined yellow triangle at the base of its abdomen gives the dragonfly its Latin name. Norfolk hawker frequent ditches and dykes in good quality fen and grazing marsh. In the 19th century it was patchily distributed throughout much of the wetter parts of East Anglia. Following drainage of fens and habitat degradation its range shrank. Towards the end of the 20th century surveys showed it to be restricted to parts of the Norfolk Broads and in Suffolk along Waveney Marshes. This made Norfolk hawker one of Britain’s rarest dragonflies and it is now protected by law.

There are a number of reasons why Norfolk hawker has never been abundant. Britain is at the northern edge of the species’ European range so climate is probably a limiting factor. The species is also associated with dykes having just the right water flow and quality and the presence of the plant water soldier. To aid its spread Suffolk Wildlife Trust has been working to improve and maintain grazing marsh and associated dykes.

Since the 1990s the Norfolk hawkers’ range has been increasing in Suffolk. At first just a few individuals were found in coastal areas near the Waveney, but the spread continued with colonisation of several coastal sites from Minsmere, via Sizewell, down to North Warren near Aldeburgh. There have also been recent sightings near Snape. Suffolk coastal numbers now make up a significant proportion of the total UK population.

Suffolk’s coastal population is particularly interesting as it is not associated with water soldier as happens elsewhere in Britain. Its behaviour is instead more typical of populations on the near Continent (where water soldier instead attracts the green hawker - a non-British species). It is just possible that the new Suffolk sub-population is of immigrant origin. Whatever the reasons, it’s great news that one of Britain’s rarest dragonflies is currently doing so well.