Thursday, 17 October 2019

Box Hill flight lines

I knew I wouldn't be away too long...

We are at the height of the visible migration season, or vis-mig if you prefer. Ed Stubbs, over at Thorncombe Street, is having a storming time this week and, apart from basking in the glory of finding a Red-throated Pipit, has written a bit about the recent history of this form of skywatching in Surrey. You can read it here.

I have been having a far more modest time, but enjoyable all the same. This morning I went over to Box Hill, and stood on the slopes between 07.15 - 10.45 hrs. My reward was a steady, if unspectacular watch, with Woodpigeons on the move (1,927 south-west), my first three Brambling of the autumn, and back-up from an assortment of thrushes, finches, Starlings, and buntings. It was time well spent. What was educational were the flight-lines that the birds took. They are crudely marked out, in yellow, above.

Firstly were the birds that flew from the north and headed south / south-west over and away from the scarp. These kept to the eastern side of Box Hill, and were viewable from the Scarp Viewpoint. If standing at the Mole Gap viewpoint, these birds would be missed.

Secondly there were birds cruising along the line of the scarp itself. These were at various heights. Again, standing at the Mole Gap viewpoint, these would be missed.

Thirdly, a small number of birds were following the line of the River Mole (mainly thrushes today) and are a bit too distant to identify if they are small passerines. Again, the Mole Gap viewpoint misses these.

So, I hear you ask, why bother with the Mole Gap viewpoint at all. Well, fourthly, there are a number of birds that use the back valley's and some of these head across the mouth of the Mole Gap, clipping the western side of Box Hill. I have had successful sky watches in these valleys, one of which you can relive here. From this viewpoint you can also keep an eye on any bird flying down the gap itself (in the picture above this is handily marked out by the road on the extreme left hand side). The river vaguely follows this road before turning sharply east, just south of Box Hill. Today little seemed to be coming down from the north and through the gap.

There is no one spot that you can take up on Box Hill that allows a 360 degree vantage point, mostly not helped by a heavily wooded crown. However, the Scarp Viewpoint is, without doubt, the best one. It also has a view across the mouth of the Mole Gap, so if birds are seen to be pouring through a quick change of viewpoints can be made. Of course, all this is weather dependent. Where the birds are coming from, and going to, at what height, and whether they can be heard calling will all alter what the observer can identify...

From Box Hill at dawn, looking out towards a misty Betchworth and Leigh


Stephen Root said...

Nice to have you back! Last time I walked Box Hill was before I started serious birding (so a long long time ago)....I must have missed so much. Fascinating stuff.

Steve Gale said...

Thank you Steven. Box Hill is a fascinating area for wildlife, but much is hidden in the woads and valleys.