Monday, 21 October 2019

Thrush-bearing cloud

When I stepped out of the house at 07.00hrs the air was laden with moisture. The weather forecast was that of a nagging band of rain stretched across the south-east of England, and unlikely to clear until the afternoon - but it's proposed edge was tantalisingly close to Dorking (according to one satellite image that I had looked at.) So, instead of heading to Colley Hill as intended, I made my way to Box Hill, hoping that the extra few miles west might make a difference in the weather.

Arriving at Box Hill made clear that it hadn't. The roads were awash with standing water, although the headlights did pick out a few Song Thrushes having a bathe. The hill top was shrouded in mist, but walking a third of the way down the scarp allowed some semblance of visibility across Dorking and on towards the Greensand Ridge. Looking south-east I could also just about see aircraft taking off and landing at Gatwick Airport, so I was ready for action. The only problem was the persistence in the drizzle, enough to be a nuisance. This was solved by finding an isolated Yew tree on the slope which I commandeered as an umbrella - this spot gave surprisingly good views from east all the way round to south-west.

The first hour chugged along with a modest number of Redwings and Chaffinches, enlivened by a few Fieldfare and single Siskin and Brambling. With little changing in the weather it was a bit of a surprise to be suddenly hit by some large thrush flocks, mostly following the scarp-line but some coming along the River Mole. The low cloud had kept them to the south of the scarp, as the higher ground was hidden from view. This allowed me excellent observation, as many of them passed directly over my head. Until 10.30hrs these two streams kept going, with Redwings outnumbering Fieldfares three to one. Flocks were generally pure of species, although the odd mixed flock did pass south-westwards. Most of the thrushes moving were in sizeable flocks, 25-75 the average size, the largest being 250.

As the drizzle abated I ventured down the slope and further to the west by 100m. And it was here that I found what I believe to be the best spot on the hill to observe visible migration. I had a good view along the scarp (both east and west), along the river and across the mouth of the Mole Gap. I was able to watch thrushes arrive from all of these directions. At this point, no doubt due to the cloud lifting a bit, a number of birds started to appear high above the mouth of the gap, having, I assumed, arrived along the crest of the downs from the east (I would have been hidden from these birds when I was standing underneath the Yew, but as the cloud was so low then I doubt that I missed any.) A number of flocks started to pitch down at this junction, landing in a small area of Yew and Beech. All 500 or so left together after only a few minutes rest, flying out over the gap, circling high. I watched them split up, with half of them crossing to the Denbigh's scarp, the others bearing west to north-west (Norbury Park area). Very few birds called all morning.

By 11.45hrs it seemed to stop, with a short burst again at 12.15hrs. An hour later I packed up myself.

There was one highlight just before I left though. I picked up a flock of eight Ring Ouzel flying along the scarp underneath me, their long-winged sleek shapes at once alerting me. All seemed to be young birds or adult females, not an adult male among them.

Final totals of the big two movers were 2760 Redwing and 804 Fieldfare. Mostly south-west.

Flight-lines today: Orange (Mole Gap), Yellow (scarp), Purple (river). Optimum viewpoint marked by green circle

6 comments:

Gavin Haig said...

Your vis mig exploits today and yesterday are making me envious, as are the tallies being chalked up down here on the coast. I have really enjoyed vis-migging when I've tried it; it's like seawatching in the sky! The trouble is (simply because of the time of year) it starts too late and goes on too long, and whenever I'm tempted to get involved I wind up losing most of the working day. Which is really naughty. Mustn't.

Steve Gale said...

Gav, I get the impression that you are undergoing a birding renaissance. Like me, after a bit of a breather you are falling back in love with it. Go on... you live right by some great vis-big spots. Be a shame not to...

ad.impact said...

Agree with Mr Gale good to see you getting your mojo back! V much enjoying your vis mig reports especially the maps which give a real insight. Tried Box Hill a month back but lucked out. Clearly need to get back asap.

Alastair said...

I used to really enjoy vismig, had a brilliant site in West Yorkshire that I covered for a while when we lived there, little vismig here though. The species and totals you're getting are great, I'd love counting all those Woodpigeons (honest Steve). Harking back to your blog demise post got me to look back at my original blog and there on the second post is a pic of myself 13 and a bit years ago with offspring (oldest is currently in second year of uni), looked a bit closer, I was wearing that shirt yesterday....

Steve Gale said...

Ad.impact - Box Hill can be a bit hit and miss, but do check out Juniper Top and Bottom while you are there.

Alastair - did you ever do any vismig when you lived in Hadlow? Wondering what the high ground in mid-Kent would be like.

Alastair said...

Never did any vismig at Hadlow or at Bough Beech Reservoir really. I do remember a few occasions at Bough Beech when the weather turned and stuff started dropping in, if I remember correctly Roseate Tern on an occasion, Black Terns and Red-b merg on another, all a bit vague now though. I ought to have a dig around amongst my old note books. I teneded to watch in the evenings there, not early morning.