Staggering into Spring

Another rather wintry spring day. I drove across the Forest in heavy sleet, although the pull of spring was still evident, as I passed two displaying curlew and opening up the main car park there was a blackcap singing. Over Ibsley Water there were 3 little ringed plover displaying and about 40 sand martin with a single swallow seeking insects. There was no sign of yesterday’s 5 little gull though, but a closer look revealed a single wheatear on Long Spit.

Elsewhere at least 11 brambling at the feeders by Woodland hide were a welcome bit of colour and a number of chiffchaff were singing.

A afternoon look at Ibsley Water resulted in an Iceland gull, which flew in from the east, bathed and then joined a number of herring gull on the western shore, however a look later seemed to show it did not stay. I got a couple of typically poor shots of it!

Iceland gull landing, the white primaries show clearly.

It was a bird in its first year of life, in plumage terms not first winter as they remain in pretty much juvenile plumage during their first winter, anyway a “young” one.

Iceland gull

Although the Iceland gull had gone by the time I was locking up there was a compensation as the ring-billed gull was there. It now looks very fine, with a completely white head and well coloured bill with a strong black ring. As I watched it gave a full long call, throwing its head back, unfortunately it was too far away to hear in the breeze.

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Thayer’s Gull

There has been much excitement in recent days at Blashford Lakes over the sighting of a potential Thayer’s gull. I say potential because these are not easy birds to identify or at least it is not easy to know exactly what you are looking at. Larger gulls are a particularly tricky bunch, they can vary quite a lot within species and not much at all between species and (even worse) sometimes hybridise!

So how do you ever know what you are looking at? For all the species there are the “Classic” birds, the ones that look like the have just stepped off the pages of the field guide, these should not be too difficult, although some genetic studies suggest even some of these might not be quiet what they seem. The others are more problematic, at least for people who like to put a name to them. Often it then comes down to looking at the various characters and scoring what is positive and what negative, after that you can consult experts or, for the more free-wheeling just decide if you are happy or not. For some there is no “right” answer, just the balance of probability.

So is this Thayer’s gull the real thing? The short answer is I don’t know and it will probably get decided by committee in the end and some will accept the decision and others not. Having seen the bird at some distance last night and then rather better tonight I have a few observations. The books often say they are structurally like Iceland gull and a claimed one I saw many years ago in Ireland was, to my eyes, identical in structure to Iceland gulls nearby. This bird looks bulkier than what I would expect for an Iceland gull, but it has the same wide, round head so typical of that species. Iceland gulls do have broader bodies and heads than herring gulls but this bird looks very heavy indeed. The wings do not look long and the rear of the bird on the water looks less attenuated than typical for Iceland, but this may be due to the rather large body size and males gulls are often a lot larger than females. As far as I can tell the plumage looks as though it has all the expected features.

Whatever it is, it is interesting and different from any other gull I have seen before, even the other one claimed as Thayer’s. It is quite obvious in the roost, it certainly stands out as different. Another way of looking at it is what might it be if it is not a Thayer’s gull? It seems American herring gull will hybridise with Thayer’s gull and that they will also hybridise with Glaucous-winged gull producing offspring that look like Thayer’s gulls. However it seems that these various hybrids tend not to have the round head, which this bird certainly does have.

If you are a bird lister it really matters if this is or is not a Thayer’s gull, importantly if it is accepted as such by the rarities committee once they have weighed up the pros and cons. Whatever they decide it is a very interesting bird and I am pleased I have seen it, I have looked at many, many thousands of gulls and never seen one quiet like it before. There is a school of thought that Thayer’s gull is just a form of Iceland gull and not a full species at all.

All this begs the question of just what defines a species, actually an important question for conservationists as rarity often drives much funding and conservation effort. A rare species will attract more effort than attract more effort than a sub-species. The definition of a species is  not a simple thing and not as clear as you might think and subject to change. Actually what matters are populations, we need to conserve populations, it does not really matter if they are species, sub-species or separate groups of one species. Keeping populations viable ensures their survival whatever their status, we should not consider them less because they are not a separate species by the current definition.

As for the Thayer’s gull, I enjoyed seeing it whatever it is eventually decided to be. Come to that I enjoyed seeing all the other gulls in the roost too. All 9,000 or so of them, including a juvenile Iceland gull, yellow-legged gulls, Mediterranean gulls and the thousands of lesser black-backed gulls and black-headed gulls. If you are interested there are pictures of the Thayer’s gull on the HOS go birding website, mine are so bad I will not torture you with them!

Elsewhere, away from the gulls, “Walter” the great white egret was on Ivy Lake and 2 black-necked grebe on Ibsley Water along with a single Bewick’s swan, a  real rarity here these days, although there were almost 200 wintering in the valley a few decades ago.

Wetlands

This week has been busy working with volunteers at both Blashford Lakes and Fishlake Meadows. Both are wetland sites, rich in wildlife and the tasks have been aimed at maintaining this diversity of habitat and wildlife. The value of many wetlands lies not in the water itself but what grows in it or immediately around it and how these species and habitats interact. They form a mosaic including open water with lush marginal vegetation, these plants act as the support for a huge foodweb, although it is often only those species such as reed warbler or marsh harrier near the top that we notice.

So what were the volunteers up to? on both Wednesday and Thursday each team was managing scrub willow, to recreate open areas, allowing in light and restarting the habitat succession. In the past such work might have accompanied by a roaring bonfire, something I moved away from a good few years ago. I have several reasons for avoiding fires, they pollute the atmosphere, they sterilise the ground with their heat at the fire site, the ash acts as a fertiliser for hungry plants like nettle and thistle and the twigs and branches burnt are potential habitat for lost of species. For years we left log piles for beetles and other wood boring species, but the smaller diameter branches and twigs were ignored, despite the fact that they support even more species. So now we avoid fires and use dead hedges wherever we can. Ultimately the wood will break down and the carbon in it be released, but much more slowly and only after use by many other species.

Fishlake’s volunteers getting stuck-in shifting willow from a reedbed area to a new dead hedge.

At Blashford Lakes the terrain was a little drier and the areas opened up will support a mixed reed and dry fen vegetation, there is also an additional reason for clearance as this habitat is favoured by adder at Blashford. Many adder populations are in trouble, with some rarely producing young, luckily Blashford’s adders seem to be doing well and we see young snakes quite regularly.

Blashford’s volunteers clearing scrub willow.

At Blashford we have combined the clearance of small willow with pollarding of larger ones to keep some dense willow growth favoured by many species. The dead hedges here provide valuable wind breaks for lots of wildlife including snakes and log piles placed in shelter are used for basking.

As it happens today is “World Wetlands Day“, this year’s theme is “Urban Wetlands – prized land, not wasteland“. Blashford Lakes is perhaps not an urban wetland, although it is not far from the town, but it is a prized wetland developed from a former industrial site, used for gravel extraction and making concrete products. Fishlake is perhaps a suburban wetland rather than a truly urban one, it is certainly right on the doorstep of Romsey town. In many ways it had been something of a wasteland since the abandonment of farming, but a “wasteland” that nature has reclaimed in a spectacular manner and well on the way to becoming a prize wetland site.

At dusk yesterday I was struct by just how valuable wetlands are for wildlife, from Ivy South hide I could see close on a thousand wildfowl, scattered all across the lake.

wildfowl on Ivy Lake

A little later still on Ibsley Water the huge gull roost emphasised how much wildlife depends upon wetlands, in this case as a roost site, as most of them spend the day feeding on farmland out on Salisbury Plain.

A small part of the Ibsley Water gull roost with a few duck in the background.

Although the Thayer’s gull of last Sunday has not returned, this week has seen regular sightings of the regular ring-billed gull and on Wednesday and Thursday evenings a juvenile Iceland gull.

 

On Show and No Show

When I arrived at Blashford on Friday afternoon to join our brilliant volunteer team for the annual “Thank you” event I was greeted with news that there had been a water shrew seen on “Pondcam”, I was a very envious! Water shrews are aquatic hunters of invertebrates and even small fish. They have long hairs on their feet and under-tail which aid swimming and are as frantic underwater as their terrestrial cousins are on land.

They are not uncommon, but not easy to see and so probably very under recorded. Just as I was bemoaning my bad luck there was a swirl of debris in front of the camera and it was back! A frenetic silver predator scattering everything before it. They look silver underwater due to the layer of air trapped in their fur. Although great swimmers they also hunt on land taking larger prey than other native shrews as befits their greater size, they are about twice the weight of a common shrew.

Blashford Lakes clocked up another “First” for Hampshire this weekend when a Thayer’s gull was found in the roost on Ibsley Water at dusk on Sunday. The finder was also responsible for the last county first found at Blashford, last autumn’s lesser scaup. Both of these species are from the western side of the Atlantic. The gull breeds in high Arctic Canada and mostly winters on the Pacific coast of Canada and the USA. Although considered as having a population of only a few thousand pairs it has been occurring with increasing frequency on the east coast of N. America and very rarely in W. Europe. Although usually listed as a full species it seems quite possible that it will be “lumped” in with Iceland gull and Kumlien’s gull, they are structurally very, very similar.

Not unexpectedly when I returned to Blashford this evening, after spending most of the day at Fishlake Meadow, there was a good crowd gathered in the hope of seeing the Thayer’s gull. Sadly they were disappointed, as it never showed up. I was not too surprised as the few Iceland gulls that have appeared in the roost over the years have almost always only been there on one evening, still it was a shame and there is still a chance it is around somewhere locally.

 

Reports received

Just in case there is not a post. Today’s reports include up to 4 bittern giving great value at the Ivy North hide, with the female smew and 2 Egyptian geese also reported from Ivy Lake. On Ibsley Water the gull roost again produced the goods tonight with at least 600 common gull, the adult Caspian gull and, at last, a first winter Iceland gull.

At Ivy North hide with the bitternfest now in full swing, the hide can get very busy, hopefully the layout allows most to get a good view, but if you are visiting please try and give everyone a chance. I know the views are about as good as can be got anywhere and it is hard to drag yourself away, but please try if there are people waiting.