Climate change: the Egrets are not alone
About 25 years ago I was visiting the seal sanctuary at Gweek in Cornwall. The sanctuary looks over the Helford River which at the time was very muddy, the water was low as it was in August, with mature over-hanging trees, a Greenshank, one of my favourite birds, was keeping me entertained.
But the Greenshank isn’t the reason why that day sticks firmly in my memory. Through my binoculars, a bright white blob suddenly appeared, obviously a wading bird with its long legs which, when it lifted them out of the mud, ended in rather comical looking bright yellow feet. I had to look at the lesser thumbed pages of my Collins Bird Guide to discover that it was a Little Egret. I assumed that such an exotic looking bird was an escapee from someone’s collection, but a little research later in the day said that this was a wild bird, already reported to the local bird group.
25 years later
Fast forward 25 years and it is not unusual to see a Little Egret standing motionless on the banks of the pond in my local park. Go to any area of water; rivers, canals, lakes, large ponds, and there is a good chance that you will come across this bird, still as beautiful as that day in Gweek, but no longer creating quite the same amount of excitement.
The history of Little Egrets in Britain is quite a remarkable one. Up until the late 1980s it was very much a vagrant bird with around 15 sightings a year usually in spring. Since then things have changed dramatically, starting with an autumn invasion of around 40 birds in 1989, with numbers increasing annually resulting in the first breeding pair in Dorset in 1996. Today’s figures, according to the BTO, are somewhere in the region of 11,000 nesting pairs with even more joining them over winter in the UK. And they are not alone, the closely related Great Egret (once quite a rare bird throughout Europe) and Cattle Egret are coming to the UK in ever increasing numbers.
The Egrets are not alone
So do you have to be a spectacularly feathered bird, like the Egrets, to enjoy this influx into the UK? Well no. If you put out seed in your garden, there is a good chance of a little grey bird with a black or brown cap visiting during the winter months, the only sometimes aptly named, Blackcap. This is a warbler and like most of our warblers they used to migrate to warmer climes in the winter. But more and more of our Blackcaps are choosing to winter in the UK, indeed some migrate here to spend the winter in our gardens. This is also true for a warbler, this time wholly aptly named, the Chiffchaff. Although still very rare, that most famous of migratory birds, the swallow has been seen to overwinter in South Wales and Cornwall and other migratory species such as the whitethroat and garden warbler are delaying their departure until later and later in the year.
So what’s driving these changes? The ‘knee-jerk’ response is climate change and that is most probably a major factor when it comes to the Egrets and the timing of departure of the migrating birds. But the picture, as always, is probably more complex than a single factor. It seems that when it comes to the Blackcap, for instance, an increase in the number of us putting out seed in our gardens is a major contributor to the numbers overwintering in the UK.
A note of caution
But there is a note of caution for any bird species eyeing these islands as a winter destination. The Collared Dove first came here to breed in 1955, having spent the previous 20 years spreading northward from its middle eastern homeland. It quickly increased in number to become one of our commonest species. However, in England at least, their numbers have been dropping quite dramatically in the last 15 years or so, again the reasons for this are not clear.
So it seems there are winners, if indeed some of these distribution changes are due to climate change, but the predicted devastating impacts of climate change will mean that there are likely to be many more losers. For every, once exotic, species that has benefited from recent environmental changes such as the Little Egret, there are many, already resident, species that are beginning to suffer catastrophic population declines.
David Withington – Consultant Ecologist