In the 1990s, East Anglian birders seeing this species locally might have noted it as a mega because it was so rarely seen in the UK, but as with the Little Egret, and more recently the Great White Egret, this ostensibly African species, the Cattle Egret, has spread its wings and found a home here. There are other species, such as Glossy Ibis, that are doing the same to a lesser degree, but may well become as common as those African egrets, given time.
The latter frequents muddy fields inhabited by hooved mammals, the other two the waterways and flooded gravel pits. Part of their spread is down to habitat formation over here but also the shifts in climate that mean they found conditions acceptable as they extended their range northwards out of Africa and then the Mediterranean region.
The Cattle Egret is the archetypal avian shytkicker, it follows cattle, horses, and sheep as they munch their way around fields and picks off the invertebrate life disturbed by the hooves; just as they would’ve done among the wildebeest and zebra in their homeland. They will also eat mice and frogs given the chance. They’re often quite grubby given they’re usually pecking about the mud of livestock farms and paddocks, but as they come into mating plumage they take on some lovely peachy feather shades within their brilliant white plumage.
Great White Egret has taken advantage of the crayfish in the lakes of Northern France. Having range extended to there several years ago, it’s not a big hop across La Manche to reach the Somerset Levels or East Anglian gravel pits.
Cattle Egrets bred in Somerset in 2008, according to the BTO website, with two pairs nesting there. There have been numerous breeding attempts since and the species is slowly expanding in southern Britain. The BTO statistics seem rather out of date, suggesting just 66 wintering birds in the UK. But, there were reports of a couple of hundred on the Somerset Levels and we have seen groups of a couple of dozen in the nearby village of Swavesey. Others report 30-40 in that same village and in and around Fen Drayton Lakes and other local areas. I hope the BTO will be updated soon. Certainly, BirdGuides no longer considers a Cattle Egret sighting as a mega these days.