Are egrets a threat to our fish?

Q) Little egrets are now a familiar sight on our local fishing lakes. My bird book says they are a vagrant to the British Isles, so when did they first become established here? Are they any threat to fish stocks?
J. PARSLOW
By email


A) Little egrets were extremely rare visitors to Britain until 20 years ago, when there was a major influx of these attractive and showy herons. They were found nesting in mainland Britain for the first time in 1996, on Brownsea Island, in Poole Harbour, Dorset. Since then they have spread rapidly and are now breeding in most counties in the southern half of the country, usually in the company of grey herons. They take much smaller prey than our familiar herons and, though the bulk of their diet is small fish, they will also catch shrimps, amphibians, snakes and insects such as water boatmen and aquatic beetles. Though unlikely to be a concern to a commercial fishery, they may be unwelcome visitors to goldfish ponds.