A WEEK spent in the Avalon Marshes of the Somerset Levels in May was almost like being in one of the great nature reserves of southern Europe, the Camargue in France or Donana in Spain, all the more welcome because of the inaccessibility of such destinations over the past two years.

The similarities were heightened by the presence of birds, once rare in Britain, which have gradually spread north due to the effects of global heating.

The rarest were glossy ibises, birds with long down-curved bills resembling small black curlews, with up to five seen flying past. They occur in small numbers in the spring lured from their regular nesting sites in southern France and Spain by our increasingly warm summers. They have made just two nesting attempts in Britain so far but are likely to become more common.

The most spectacular birds, for which the area is becoming famous, were the great white egrets, the size of our familiar grey herons but with longer necks. Back in 1970 as few as 170 had been recorded across the whole of Europe but their northward spread from Africa has been inexorable.

Shapwick Heath, on the Somerset Levels, was home to the UK’s first breeding pairs in 2012 and they have been present in slowly increasing numbers ever since. We watched them at Ham Wall RSPB Reserve (pictured) next to Shapwick Heath.

The Somerset Levels provide an ideal mixture of habitats for the egrets with open wetland, reedbeds and grazing marsh amid drier farmland. The nearby Severn estuary offers additional resources, especially when other areas are frozen.

They are now no longer classified as rare in Britain with a wintering population of perhaps 35 and birds are occasionally seen further afield as they disperse after breeding, turning up at wetlands like Leighton Moss with one even stopping off at Lindley Wood Reservoir six years ago.

Alongside the great whites were little egrets, now much more familiar but once rare visitors from the Mediterranean. I remember seeing my first in the Camargue over fifty years ago but now they are seen regularly along the Wharfe and at Otley Wetlands. Dozens can be seen at Leighton Moss.

Last year one even flew over our Otley garden and I wondered whether it was too fanciful to imagine one dropping down to investigate our garden ponds. Perhaps not, given that we get occasional visits from a heron in search of frogs and newts. I live in hope!

wharfedale-nats.org.uk