In the winter of 2005/06, some 40 intrepid volunteers made a fairly
intensive Atlas-type survey of a single 10-km square. The 10-km square was
SU52, the area bounded roughly by Marwell – Cheesefoot- Cheriton- Corhampton.
We chose this square partly because it is the nearest square to the centre of
the county, partly because it’s a square not normally well covered, and partly
because it’s fairly typical of much of Hampshire.
The purpose of the exercise was to test some of the methodologies that may
be used in the forthcoming national & county Atlas projects (starting in
November 2007).
Members of a "Tetrad Team" of observers confined each of their visits to a
specific tetrad (2km x 2km square), and they recorded birds seen in each
20-minute period. Two visits, mostly of 3 hours, were made to each of the 25
tetrads in the 10-km square. People in a "Rover Team" team had a much more
flexible brief, and went wherever they chose within the 10-km square, for
whatever length of time, and making as many visits as they wished.
First, some statistics:
| |
Tetrad Team |
Rover Team |
Total
|
| Number of
observers |
22 |
11 |
33 |
| Number of
visits |
49 |
66 |
115 |
| Number of
hours |
142 |
154 |
296 |
| Number of
species |
74 |
77 |
81 |
It definitely was intensive coverage, and I’ll doubt we’ll be able to do
that for every square in the main Winter Atlas!
I guess the most interesting thing, was that the overall total and range of
species was very similar for both rovers and tetrad people. This wasn’t too
surprising given the total time spent, and that both teams spent roughly the
same time overall. The results from tetrad people, gave a better picture of
bird distributions, whereas the rovers were much better able to seek out
specialist species like wetland birds and owls
What about the species ?
Well, there were no great surprises. Water birds were of course hard to
come by, with only a tiny bit of water in the whole square. The rover team
were able to concentrate a bit more time on this aspect, and were able to
record a few species not encountered by the tetrad team - singles of Mandarin,
Tufted Duck, Green Sandpiper and Kingfisher. Of the widespread birds,
Woodpigeons were of course the most numerous, and on their second visit, over
8,000 were recorded by the tetrad counters. Specialist farmland birds included
plenty of Yellowhammers, but relatively few Grey Partridge, very few Corn
Buntings, and no Tree Sparrows at all. Skylarks flocks were relatively few in
number, perhaps because the square is relatively well-wooded. But pleasingly,
and presumably for the same reason, farmland Woodlarks were reported from
several widely spread locations. Of the finches, Bramblings were more numerous
than Greenfinches and Linnets, and there was a scattering of Reed Bunting and
Redpoll. There were several small flocks of Fieldfare, but Redwing were
decidedly scarce. Some lucky participants were able to see flocks of Golden
Plover, and other "nice" sightings included Peregrine, Red Kite, Lesser
Spotted Woodpecker, and Hawfinch.
There is a lot of interest in the detail, and a fuller report appeared in
the 2006 Hampshire Bird Report.”
Glynne Evans
Chairman, HOS Scientific Committee & Atlas Steering Group
