Friday, 6 May 2011

Its a date with Dolomedes fimbriatus

Yesterday I had a hot date with a rare and exotic female, no not Catherine Duchess of Cambridge, but the beautiful raft spider, Dolomedes fimbriatus.

We travelled up to the Shropshire Mosses and Meres to see this beauty. There are two raft spiders in the UK, the very rare Fen Raft Spider, Dolomedes plantarius which is only found at a handful of sites in East Anglia and the South East and the widespread but very localised in distribution raft spider. Bizarrely the rarer of these two is quite well studied, however the ecology of fimbriatus is hardly understood at all. And they're not easy to find either in boggy landscapes, unless that is the big females are on water. And when I say big, I mean big.... they'd give the canny lasses in Newcassel on a Friday night a run for their money. Yep that big.

But before I allow you to see this big lady, let's have a crafty peek at the weedy, pale wimpish male raft spider above. There were quite a few scuttling about in their meek lily livered way, but even these had a style of their own, so well camouflaged too. But then we found a female, well camouflaged too but absolutely stunning.........

These are just stunning arachnids. And yes the female is huge, the biggest spider in Europe. The one below was about 7-8cm long from leg tip to opposite leg tip, the body about 3cm.

These photographs don't do this spider justice as the body was like chocolate brown velvet with a lemon curd go-faster stripe down each lateral side. As hunting spiders they spend a lot of time waiting for prey on water, using water tension to support their weight. However they are attached to a piece of vegetation using their hind legs and a tiny thread of silk.

One curious piece of this species ecology is that if a male approaches to breed and she thinks, nahh far too weedy, she just eats him. Not after mating as many spiders do, but before mating. Now that does have a slight ecological problem in that if the last female was on the planet, would she eat all the males and become extinct?

I'm glad we found some spiders as with this very dry spring we're currently experiencing the Moss we were visiting was almost dry. The two females we found were actually in puddles around an ancient tree stump, this was the only open water we found. We need rain, and lots of it soon.

If you want to find out more about these fascinating beasties, I'd recomment the Dolomedes website http://www.dolomedes.org.uk/

Wednesday, 4 May 2011

Seawatching at Severn Beach

Yesterday evening after work I headed over to Severn Beach in South Gloucestershire following a call at lunchtime by Bristol naturalist Ed Drewitt that the evening before hundreds of terns, godwits and other waders had flooded the sky en-route to their breeding grounds further north.

We had all been reading for the last few days amazing reports of 1500 'commic' terns, 4-500 godwit flocks, whimbrel, dunlin and even 40 dotterel in summer plumage passing through. In recent days strong easterly winds had blown many migrants westwards, rather than following their usual route along the English Channel. This spring has been a fantastic time for sea watching up the River Severn. So after work, I joined Ed and another colleague and we sat down in the shingle awaiting the arrival of high tide, and the birds of course, while admiring the charming view of the massive Avonmouth industrial complex a few miles down the coast. Lovely. But the birds don't mind.

Soon the rising tide pushed up a smallish flock of bar tailed godwits who began feeding just in front of where we sat, joined by a lone knot (centre of picture). I've never seen these birds in summer plumage and they were stunning with their brick red bellies. What is amazing is that only 3 days or so these godwits would have been feeding in West Africa and in a few more days will be in the Arctic tundra. Bird migration is amazing.

We then had some whimbrel who warbled their wonderful flutey call as they restlessly skipped about in the rising water, followed by 12 black headed gulls on migration, quite a few swallows and house martins flying through, a sanderling, a couple of ringed plover and a few dunlin in their fantastic summer plumage with golden top and black bib belly.

But sadly nothing like the numbers Ed had experienced the evening before where the Severn Bridge, a well know barrier to bird migration had stopped 500 terns in their tracks and they then wheeled round to gain height right over Ed's head. We did however really enjoy the 2 hours out there on a glorious spring evening, such a nice thing to do after work, and we did have the godwits above fly low over our head calling.

And so as the sun set, the temperature dropped quickly. It was therefore time to go home from this wild feeling place, just on the outskirts of Bristol, and have a cup of tea.

I'll finish though with one amusing thought. As we sat there Ed's phone rang, another birder he knew was a mile or so down the coast and sending reports. Ed's phone rang a second time, another group of birders further north reporting sightings. Through binoculars we could see most of these birders from our vantage point, which added to the excitement having these updates from north and south of us. Mobile phone reports of those wild birds being very mobile themselves on migration.

Sunday, 1 May 2011

Broad Bodied Chaser

I spent yesterday catching up on gardening and housework duties, and was very happy to see this female broad bodied chaser resting herself on the willows at the back of the border.

These may be one of the most abundant dragonflies in Europe, but they're still wonderful. And emerging in April is quite early.

A holly blue butterfly also entertained for a while as did a willow warbler. Above my head swallows and house martins prospected for nesting sites. Not a bad wildlife tally, just working and relaxing at home.