Monday, 29 November 2021

Finches, snails and Zoom.

First there was the hooley, it wasn't so bad here, and it coming from the north the house was sheltered. Taking the pony into the field I struggled to make progress though, two steps forward and one back. Then there was the snow; Saturday night. So yesterday, before various trips to the airport - plane takes off, plane breaks, plane goes back to Glasgow, flight cancelled, replacement bus service to Edinburgh, flight from Edinburgh in the evening.... I walked the hound at Marwick. I was hoping for WW gulls but there weren't any. Indeed there were relatively few gulls of any description. There was snow on the beach though, which I kind of like, photographically. 

More pix at shortly.
Between trips to Kirkwall, of course I'd set off before learning the flight had turned around, I went to Scapa. I was hoping for a Little Auk at least and a Brunnich's Guillemot would have been tasty. However, when I arrived, unusually, someone was zooming about on one of those jet ski things. Bloody noisy, shitty things. No birds. Well, there was a hybrid crow on the beach, a confidingish Herring Gull and a juv Shag outside the harbour but close in. (I had glimpsed a northward heading likely Little Auk at Marwick.)

Hybrid Hooded/Carrion Crow somewhere in the mid-dark - dark crow categories -

Adult Herring Gull.

Juv Shag.

At home I'd looked out on a flurry of finches under the feeders, some 60 Chaffinch, 15 or so Brambling and the usual Greenfinches and Goldfinches in attendance. I didn't have time to check the birdcrop with all the toing and froing. However, a Woodcock under the trees was just the second of the autumn.

Not the best images but you get the idea.

There was a post on another blog I follow about the lack of Greenfinch at feeders of late. This prompted me to have a play with Birdtrack and download some graphs. If you keep consistent data from a site Birdtrack is a very useful tool, although I have a suggestion or two about different graphs that would be useful to generate. So slightly clumsily here is some comparitive data from my main recording area.

The scales are slightly different, so caution, but the pattern is obvious, I could fill in the gaps with all the years, but it makes it harder to see, trust me, they just reinforce this pattern of decline.

Greenfinch, peak count per week 2013.

Greenfinch 2021 so far.

This late autumn peak is a consistent feature, however, the numbers for the rest of the year for the last three years have been low. I need to make a clever line graph, unfortunately Birdtrack doesn't generate that automatically from the menus.


During the week I had a wander in Binscarth Wood. I was after the larva of the hoverfly Dasysyrphus albostriatus which was found as a larva a week or so ago, so, yes, another hoverfly twitch.

The larva can be found amongst the lichens on tree trunks. In the unsuccessful search for this species I came across a snail I'd not found before.

I identified this as Clausilia bidentata, common enough in the UK but restricted to a few sites here in Orkney, although, following up by looking at a Field Club paper from the 2013 Bulletin common enough in Binscarth. I should have found this before. Many thanks to TC and IS for confirming the ID. I'd remembered the Field Club paper and this prompted me to go through some back issues. There is lots of good stuff in the Bulletin. Plenty of clues for species to target in 2022 (more of that at a later date).

During the week I've attended two Zoom meetings one on the identification of adult caddis which was useful.

Here are some images I took this week of Stenophylax permistus from here and from Yorkshire, genitalia images to prove the ID.

Female Stenophylax permistus from Yorkshire, October.

Male Stenophylax permistus from Orkney, August.

The other Zoom meeting was from the Orkney Field Club, personal observations of Common Carder Bees nesting in a garden wildlife lawn. This was truly excellent and was followed by a very interesting discussion about species northward migrations due to climate change, and parasite and host relationships, amongst other things. Those were the bits that really interested me, anyway.

One of the bloggers I follow was musing on their loss of expertise with birding because they've branched out to look at other Classes in recent years. My personal view is that the branching out has given me a fuller and more holistic understanding of the natural world, but I do agree that new knowledge does come at the expense of old as the brain discards what is no longer used, or at least puts it on the "external" harddrive.


Simon Douglas Thompson said...

The greenfinch capture is incredible!

Alastair said...

Simon, that's a bit of an old photo from 2015 using an action cam mounted on the birder feeding stick. I think I'd set it to fire every few seconds, a real bit of luck. I have a plan to try to repeat the shot with some proper gear tho, it will require a lot of luck to get anything as neat as that tho.