David Bradley – Page 67

Why do crabs walk sideways?

Edited straight from the Wikipedia entry on hermit crabs

As the hermit crab grows in size, it must find a larger shell and abandon the previous one. Many species form housing chains to get a new shell. When an individual crab spots a new empty shell it leaves its own shell and tries the vacant shell for size. If the shell is too big, it goes back to its own shell and waits near the vacant shell.

As new crabs arrive, they do the same forming a group of dozens of individuals, holding on to each other in a line from the largest to the smallest crab.

As soon as a crab arrives that fits the vacant shell and claims it, leaving its old shell empty, then all the crabs in the queue swiftly exchange shells in sequence, each one moving up to the next size.

The answer to the title question…because they do like to be beside the seaside, oh they do like to be beside the sea…

Eyes are a worry aren’t they? I use mine a lot…but I have all these little floater things bobbing about, I see them when I use my PC, when I’m on the phone, when I’m outside on a sunny day, sitting reading, watching TV, playing guitar, taking photos, singing.

All the time, actually.

They’re always there. I was getting worried.

Couple that to the need to find my glasses to read anything at all or look at an object any smaller than an inch across, and it’s all a bit worrying.

So, nice to have an eye test where nothing truly untoward is revealed, just a slight and inevitably sliding into age-related long-sightedness and a new prescription for computer glasses and reading glasses. Those floaters, apparently, I’ve not got many at all, all very normal and healthy in there. Look, here’s your retina, how healthy is that?

Oh, but there’s glaucoma in the family and my eye pressures were slightly different from each other (15 in the right eye 19 in t’other). That means I have to have a so-called “field test” Look at the tiny, faint white lights on this screen and click a button to say you’ve seen one as they illuminate randomly across your field of vision.

I was not seeing the light in the field test, well, one faint point. I was consistently missing it in the test and had missed the same point point the last time…retinal damage, something amiss? Immediate neurotic conclusion is that blindness is coming and I need to get to the hospital urgently, but also my inherent urgent not to be anywhere near a hospital despite chronic hypochondria had me making a request of the optician:

Can I do the test again just to be sure?

Of course!

So, I did it all again and this time I scored 100% for both eyes. Didn’t miss a single point of light across my visual field, so that’s good, no damage, just a transient, albeit repeated, ocular glitch. All good. Pressures tests showed both eyes the same, give or take, 13 and 14 units; smack in the middle of normal.

My new computer glasses do look a bit trendy and they let me have a Calvin Klein case for them, even though they’re not CK, so any fashion-conscious friends can feel envious. I will undoubtedly wear that at gigs so I can see my music, they’re focal length is a couple of feet, which is right for PC monitor and music stand alike.

Eyes really are a worry…

Mistle Thrush and Mistletoe

Mistle Thrush (Turdus viscivorus) in our mistletoe-infected rowan tree. I was poking the camera out of the bedroom window hoping to catch sight of the Goldcrest (Regulus regulus) calling from our bushes when a male Blackbird and this Mistle Thrush had an altercation and the Thrush ended up perched in the tree right in front of me.

He’s been around for a couple of weeks now, but spends his time hiding in a neighbour’s tree which has lots of berries and lots more female mistletoe (with berries), our rowan has already had all of its offspring predated by birds and the mistletoe growing on ourÂ tree, as you can presumably see, is male, so no berries.

We are assuming it’s the same Mistle Thrush that roosted in their tree last winter; life expectancy is three years, but can be much longer, and, of course, much shorter. They are a resident species and territorial they will scream their cackling call and fend off other thrush-type birds that try to feed on their berries. We hadn’t seen nor heard the bird since last winter, so presumably it was active elsewhere in the area through Spring and Summer and into the Autumn.

Aside from the more raucous call and song that sets it apart from the dulcet tones of the Song Thrush and even the Blackbird, the bold, brown spots on the cream breast of the Mistle Thrush do not have the “heart” or “arrow” shape of those on Song Thrush. The BTO has a nice video describing the distinctions between Song and Mistle.

Long exposure trees

It’s an old photographic trick, set a relatively long exposure time and move the camera while pressing the shutter and after, you get blur. But, if you’ve got focus on the subject you might just get some nice abstracts. Here are a few efforts in a local woodland (Fen Reeves Community Wood). Most of the photos were down swinging the camera vertically either up or down. The second-last one below, above the orange and brown Autumn Leaves, one is a horizontal swing.

Horizontal swing. 1/2s f/11 160mm ISO200

“Autumn Leaves” Worts Meadow Nature Reserve, Landbeach Long exposure, 1/2s f/22, 600mm, ISO100 with vertical movement of camera during exposure.

Developing murmurations in Cottenham

For those of you intrigued by such things, you might like to know that the scale of the Starling flock murmurating into the reed bed at the Broad Lane balancing pond in Cottenham has increased by an order of magnitude since I last took a look.

On my first visit this year, I estimated 3-4 flocks of 200-300 birds. This evening just as the sunset, there were 3-4 much bigger flocks each of three times those number and several smaller flocks of 100+ thereafter. Estimate the total number of birds roosting there at 2000-3000 at the moment, which is about 1000-1500 fewer than the peak last winter. More will arrive from Europe as winter chills come on I suspect.

At the moment, they’re bedding down in quick succession. If there were raptors around, mainly Peregrine falcons or perhaps owls, they’d murmurate longer before going to roost to avoid being taken on the wing or caught just before hitting their reed bed.

Life on the allotment #AllotmentLife

We’ve done a lot of digging this year…me with the pond and half the allotment and Mrs Sciencebase the other half of the allotment. On a misty Sunday morning in November, there was still digging to be done and a few peas to be shelled for a sweet snack, but I opted to snap

Short-eared Owls at Burwell Fen

Short-eared Owl with prey, Burwell — Short-eared Owl with prey, NT Burwell Fen, 10th November 2019

We went looking for Short-eared Owls again at Burwell Fen having heard from a friend that there were “twitchers” huddled together spotting them earlier in the week. We have been to the Fen a few times this year, but not seen the owls since February. However, I learn from local birding expert Hedley Wright that one of last winter’s “flock” (we had more than six there last Winter) had spent its summer on the Fen too presumably having decided not to return to Scandinavia for the breeding season for some reason.

Two Short-eared Owls, NT Burwell Fen, 10 Nov 19 — Two Short-eared Owls, NT Burwell Fen, Sunday, 10th November 2019

Anyway, we saw a Kingfisher dart back and forth along the almost dry ditch in the middle of the Fen and then Mrs Sciencebase was first to spot one in the distance close to the electric power installation on the edge of Burwell. And, then a second. There were several bird photographers around, but I wouldn’t describe any of them as “twitchers” and maybe not even “birders” as such, there is a distinction (see my birding glossary).

There have been sightings of more than one SEO since the end of October 2019, and yesterday (10th November), it seemed that there were perhaps three or maybe four. We never saw two at a time, but were aware of two in the air while another was out of sight in the scrub a few hundred metres in front of us.

Short-eared Owl,, NT Burwell Fen, Sunday, 10th November 2019 — Possibly a third or fourth SEO at Burwell

Two of the owls were forced aloft by Rooks at different times. Rooks really don’t like raptors and owls in their territory and will harangue, harry, and harass them endlessly to get them to move on.Â One of the SEOs has a very apparent feather injury to one wing.

Ponies and Shorties, Burwell Fen, Cambridgeshire

I’ve mentioned Burwell and Tubney Fens previously, depending how you approach them, they are the back end of the NT Wicken Fen area. The semi-feral Konik ponies (Equus ferus caballus) of Polish descent there along with longhorn cattle (Bos primigenius) and European roe deer (Capreolus capreolus), are natural managers of the scrub.

The area is almost perfect roosting and hunting for Short-eared Owls, which have once again returned from Scandinavia to the Fen for their winter break.

Starlings seem to find rich pickings around and on the Konik ponies of Burwell Fen

There were three to four showing quite well and being harried and harangued by Rooks on the wing high above the fen.

I don’t think any of the clutch of photographers (Homo sapiens phoographiensis) photographing the birds got any particularly close views, but there’s the rest of the winter to try before the birds fly back to their summer breeding grounds next March.

Throwaway capture of a Kingfisher at Burwell Fen

100th Anniversary of Remembrance Sunday

It’s one hundred years since the first Remembrance Sunday was held to mark the first anniversary since the ending of World War I. As ever, we were there to attend in our Sunday best with our poppies worn with pride.

Cottenham Remembrance Day Parade 2019