Booming populations
Although climate change will have a devastating effect on many of our birds, warmer temperatures are encouraging other species to stay and breed in the UK’S marshy environs
How warmer temperatures are encouraging some birds to stay and breed in the UK
BACK IN THE 1970s, when I first started birdwatching, ID was pretty straightforward if you saw a long-legged, long-necked bird. Bitterns were extremely rare in the UK (and even now, how often do you see one well?), and Spoonbills were gone, seemingly forever, so the Grey Heron had the field (or should that be the marsh?) pretty much to itself.
How things have changed. In southern England, at least, and increasingly further north, birdwatchers now stand a chance of seeing a whole host of herons, egrets and similar species, and there might well be more to come.
The pioneers
In fact, though, it’s often cited as a case of recolonisation. Spoonbills had become largely absent from the UK from the 17th Century onwards, with only occasional single pairs breeding and a handful of passage birds seen each year, largely in the spring. The destruction of much of their preferred habitat, as fens and swamps were drained for agriculture, was the main culprit for their demise, although hunting and then egg collecting took their toll, too. But, in 2010, came the announcement that at least four pairs had fledged young at Holkham National Nature Reserve in Norfolk – the first breeding colony for more than 300 years. Spoonbills typically breed in single-species colonies or, as at Holkham, in small groups within mixed-species colonies containing other water birds, such as Grey Herons, Little Egrets and Cormorants, so expansion in numbers and range can be a slow process. Once it gathers momentum, though, it can really take off, and as more and more Spoonbills also winter in the UK, the potential for the Norfolk colony to sprout outliers rapidly is great. It needs a mixture of freshwater lakes, reedbeds, and brackish lagoons, so will always be tied to coastal areas, but it could benefit from plans to create natural sea defences in many areas by means of planned flooding and managed realignment. It was a similar story with the Little Egret. It was once probably common and widespread in Britain and Ireland – they were listed among the birds eaten at the coronation feast of Henry VI in 1429, and 1,000 were eaten at the enthronement of George Neville as Archbishop of York in 1465. But habitat loss, over-hunting and a cooling climate saw them decline rapidly, so much so that Thomas Bewick, in the first years of the 19th Century, described them as almost extinct. Things got worse. Egret plumes became the must-have fashion accessory, to the extent that, in 1887, one London dealer sold two million egret skins. Most came from the hunting of wild birds, with disastrous effects, and by the 20th Century, it was a bird of southern Europe only. This catastrophe did spark a reaction, though, and in 1889, the Plumage League was formed, a conservation organisation that would become the RSPB we all know today. Conservation action in continental Europe helped the Little Egret population to grow rapidly, until it became common in western and then northern France, and breeding took place in the Netherlands at the end of the 1970s. Throughout this time, it was a rare vagrant to Britain, but records became more and more regular, until in 1996, a pair first bred at Brownsea Island, Dorset.
From there, its numbers and range have expanded as far north as Scotland, with breeding numbers now estimated at 750-plus pairs, and wintering numbers pushing up past 5,000 birds.
The next wave
All fairly straightforward, so far. Spoonbills and Little Egrets are both largely white, so can’t be confused with Grey Herons, and the former are distinctive by virtue of their spatulate bills, used to sweep through the water in search of food, and their habit of flying with their necks outstretched. In the last few years, though, increasing numbers of Great White Egrets have been seen in the UK, closely followed by Cattle Egrets. The former, Grey Heron sized but also all-white, bred for the first time in 2012, at Shapwick Heath Nature Reserve, Somerset. The number of wintering birds continues to increase, with south coast sites such as Dungeness being particularly good spots to find them, so the likelihood is that they’ll become a regular breeder, and that their population might expand along the same lines as their smaller relative’s. Their even smaller relative, the Cattle Egret, is a species that has expanded its range worldwide by a huge amount in the last century – it even crossed the Atlantic and is now seen in large numbers in parts of South America, and is one of only two species (the other is the Arctic Tern), to have reached all seven continents. It’s perhaps surprising, then, that it has taken so long to make inroads into the UK, but the story has been much the same as with Little and Great White: increased numbers of wintering birds, with invasions in 2007-8 and last winter, and first breeding in 2008, again in Somerset. Given its global success, and the fact that the population in northern France is thriving, expect it to become a familiar sight in Britain, far from its origins on the African savannah.
Coming soon?
So what’s next? Well, Glossy Ibises might be a good bet. There’s a good population in southern Spain, and increasing numbers of these birds have wintered in Britain in the last decade. Inevitably, that resulted in a breeding attempt at Frampton Marsh RSPB, Lincolnshire, in 2014, and although it wasn’t successful, it’s unlikely that they’ll stop there. It needs well-vegetated marshland, and wet meadows, a slightly different requirement than some of the other species under discussion, but all the indications are that at least a small breeding population will establish itself. There’s also the beautiful Purple Heron, a pair of which bred at Dungeness in 2010, the same year that a pair of Little Bitterns bred at Ham Wall in Somerset. Both are birds with fairly specialised habitat needs (shallow, marshy lakes with large reedbeds for Purple Herons, and reedbeds generally, for Little Bitterns), so it’s hard to imagine them emulating the success of the egrets, all of which are much more generalist in terms of diet and habitat. But there’s no reason why a relatively small but stable breeding population shouldn’t become established in the next few decades, in southern Britain at least. Longer shots are Night Heron (another species with a very wide range worldwide), and Squacco Heron. Both appear here as vagrants on a regular basis, and Night Heron breeds as close as northern France, so a cross-channel hop is certainly not out of the question. Of course, we’ll let you know whenever that does happen!
Why?
All of which begs the question as to why these birds are doing so well in the UK, at a time when so many species are under pressure. Two main reasons present themselves. One is the warming of the climate. For example, the disappearance of the Little Egret after the medieval period is thought, at least in part, to have been due to the ‘Little Ice Age’. So as temperatures have increased, so the birds have found the UK more to their liking. That’s true of pretty well all the species discussed – although some are migratory and could head south to escape the worst of the winter weather, they prefer to be somewhere warm enough that bodies of water don’t freeze and that prey items remain plentiful, and wet enough that wetlands (and surrounding agricultural fields, etc) don’t get too dry. Secondly, and perhaps more importantly, the expansion of wetland habitats in the UK has given all these species somewhere to breed and feed. Conservation schemes, supported by the European Union’s Life-nature programme, have restored wetland habitat, and created new areas, often on former industrial land. The biggest beneficiary, perhaps, is a bird that so many of us rarely see, even when we know it’s present – the Bittern. In 1997, there were just 11 booming males, at seven sites, but by 2014 this had grown to 140 at 61 sites, with Ham Wall in Somerset the most successful – it has had as many as 20 birds booming at one time. The restoration and creation of reedbeds was obviously important for them, but it also had the spin-off effect of creating good habitat for other herons, egrets, and similar birds. Large, landscape-scale schemes such as the Great Fen Project promise to extend that success further, although Brexit creates uncertainty about the extent to which some of the projects will be able to continue. Climate change looks likely to see the loss of a number of breeding species to the UK – mountain-dwellers such as Dotterel and Ptarmigan are among those under threat – but the rise and rise of the heron and egret family, and similar birds such as the Spoonbill, may provide us with some sort of consolation. Learn to ID the 12 species on the pages overleaf, and you stand every chance of finding something unusual for your #My200birdyear list on your next visit to your local wetland. And if you do, report it to your county bird recorder or on the BTO’S Birdtrack app, and tell us about it by emailing birdwatching@bauermedia.co.uk – you could help identify important breeding and wintering sites that can be managed to bring in even more birds.