Watch almost any wildlife film set in Africa and you’ll see big game animals with small white herons riding on their backs. Cattle egrets were, until a couple of decades ago, very much birds of the tropics, although they also flourished around the Med. Today, in my home county of Somerset, I regularly see flocks of 100 or more, usually feeding around the feet of livestock, and occasionally hitching a ride on their backs. Cattle egrets arrived here in 2008, breeding for the first time in Britain that spring. This was soon followed by the two harshest and coldest winters so far this century. Our local cattle were taken inside and the egrets fled back to the warmer climes of mainland Europe. It has taken them a few years to return, and even now, a brief cold snap – like that of December 2022 – will mean a full-scale retreat. But they are breeding in large numbers, and recently a flock of almost 700 birds was counted going to roost. Most of us welcome these gawky yet strangely charismatic birds, the third egret species – after little and great white – to colonise southern Britain. Yet I have also heard them described as “climate refugees”, and it is true to say that without the recent rise in average temperatures, they would have stayed put.