Yesterday evening I went to an amazing sand martin roost at Tinker Joe's Flash, Plank Lane, Leigh. An estimated 5 - 7000 sand martins came in and they swirled around in murmurations that would be the envy of many a starling roost. I've never seen so many sand martins before, a truly breathtaking sight, one of the greatest wildlife spectacles I've ever seen, right on my doorstep in Leigh!
Just for a bit of fun I thought I'd have a go at estimating the numbers by putting a very crude grid on one of my sand martin photos. In the field we'd estimated 3 - 5000 birds, and I just wondered how accurate we had been. I haven't counted every bird in every square on this image, but I have counted birds in every other square, and for the rest estimated the number based on counted squares if you see what I mean. If you add up the totals for each square it comes to 4005 birds. Bearing in mind that not every bird is on this photo because there were smaller flocks on the periphery of the main swarm, an estimate of 5 - 7000 birds might have beeen more accurate. Even so, not a bad attempt in the field!
Brilliant Colin! Is this likely to be just a one off or will they stick around for a while/
ReplyDeleteSorry for the late replay Andrew, It's been a bit manic recently. It's not a one off because they've been roosting here for a week or two now, but they will move on soon, probably when the weather changes. I've not heard about them recently, so they might even be gone by now.
ReplyDeleteOk, thanks Colin!
Delete