Friday, 10 December 2010

British Trust for Ornithology - Bird Atlas

Before I start, this blog entry don't have any pictures of birds in it, 'cos to all intents and purposes there weren't many birds!! Also, my routes through the tetrads weren't equal, but covered all the habitat typical of each.
On Thursday last, the weather being sunny, I took the opportunity to do the first winter atlas survey on the two squares I volunteered to do on Romney Marsh proper. Here they are, TQ02 J & P on the map, the routes I walked have dotted red lines alongside


As the frost was just coming out of the ground, it was heavy going on the bare earth as I followed the footpaths across stuff like this

and this is how it clagged up my boots - blimey it was hard work, and if I had stopped for more than a few seconds the chances are I could not have set off again!!

The snow was still lying on the hilltops, and believe me, this is a serious hilltop for Romney Marsh!

and also on the steep valley sides, just the sort of terrain where the Romney Marsh Mountain Rescue squad are busiest this time of yesr

Anyway, off I set alongside the Brenzett Sewer, which is a serious drainage waterway, and probably dates back 300 years or more


This dyke runs fairly straight for a half-kilometre or so, then kinks, at a spot where the ground is about a metre higher, I wonder why?

Birds were few and far between, no doubt due to the recent severe weather, for even allowing for its low altitude, on Romney Marsh the weather often doesn't take prisoners. This is illustrated by this telegraph pole, a relic without doubt of the night of 16th October 1987, but there is also a glimpse of the habitat across the marsh, hedgerows with mature bushes, and isolated gardens

And a few lengths of denser, more mature hedges with trees, home today for most birds recorded - winter thrushes

Then there are the reedy dykes, home in many places to the rare Greater Water Parsnip (Sium latifolium) and, I hope come the spring, Reed and Sedge Warblers

Although the hedges are an important food source for winter birds, these sloes seem to be past their best and look very unappetising to me


Here's a glimse of another magnet for birds on the marsh, sheep feeding stations, where today I recorded a Lapwing and a Yellowhammer!!

 Now, here's a grumpy old moan -
The BTO atlas is apparently based on a sample of Tetrads across the UK, and statistical analysis of what we find therein during a one or two-hour walk through each, recording what we see. From this I believe the BTO can then calculate a statistical representation of relative abundance. This survey did not need EVERY tetrad to be surveyed to achieve this to a statistically relevant degree - but most of the County-based ornithological societies have since decided to try and survey every tetrad across the UK. Added to this, surveyors are being asked to look for "under-recorded" species, and go out of their way to "get" rare or uncommon species - WHY??. To do this immediately introduces a  bias into the relative abundance calculations - I dont know the proper statistical term for this, but it seems to me best described as buggering up the coupon, and I detect an element of "overgrown trainspotting", often prevalent among twitchers and listers in this. I wonder why the BTO is going along with this, maybe they are happy with the raw data it will produce but I can't see it being statistically significant somehow.
Having read this, you are entitled to ask why I have done the extra tetrads - well, I enjoy doing this kind of  birdwatching, it's fun and good exercise - especially yesterday - provided you dont take it or yourself  too seriously!
Now then, what did I find? Well, not a lot -
Carrion Crow 9
Yellowhammer 2
Common Gull 6
Snipe 1
Woodpigeon 34
Meadow Pipit 1
Blackbird 16
Fieldfare 35
Great Tit  3
Blue Tit 5
Chaffinch 1
House Sparrow 10
Tree Sparrow 1
Song Thrush 4
Starling 1
Pheasant 1
Redwing 35
Jackdaw 2
Dunnock 1
Lapwing 1
Wren 1

I look forward to seeing what I find in February, and again in April/May, and June/July, when I shall blog again, but will I then be grumpy once again? - wait and see!!


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