
The British Trust for Ornithology (BTO) have been running a garden birdwatch since 1995.
The idea is simple - volunteers throughout the U.K. keep a note of the numbers of each species they see in their own gardens each week.
Here are the results from our own small suburban garden for last month:
| Species | Week Commencing | ||||
|---|---|---|---|---|---|
| 2007-03-30 | 2008-04-06 | 2008-04-13 | 2008-04-20 | 2008-04-27 | |
| Blackbird | 2 | 2 | 1 | 3 | 2 |
| Blackcap | 1 | 1 | 1 | ||
| Black Headed Gull | |||||
| Blue Tit | 3 | 1 | 1 | 1 | 2 |
| Chaffinch | 2 | 1 | 2 | 1 | 1 |
| Chiff Chaff | |||||
| Coal Tit | |||||
| Collared Dove | 2 | 1 | 2 | 3 | 3 |
| Crow | |||||
| Dunnock | 2 | 1 | 2 | 2 | 2 |
| Feral Pigeon | |||||
| Garden Warbler | |||||
| Goldcrest | |||||
| Goldfinch | 3 | 3 | 3 | 2 | 3 |
| Great Tit | 1 | 2 | 4 | 2 | 1 |
| Great Grey Heron | |||||
| Greenfinch | 3 | 2 | 3 | 2 | 3 |
| House Sparrow | 4 | 5 | 5 | 6 | 5 |
| Jackdaw | |||||
| Kestrel | |||||
| Linnet | |||||
| Long-tailed Tit | 2 | 1 | |||
| Magpie | 2 | 2 | 1 | 1 | |
| Merlin | |||||
| Mistle Thrush | |||||
| Pied Wagtail | |||||
| Robin | 2 | 2 | 2 | 2 | 2 |
| Siskin | |||||
| Song Thrush | |||||
| Sparrowhawk | 1 | ||||
| Spotted Flycatcher | |||||
| Starling | 3 | 2 | 2 | 3 | 2 |
| Stock Dove | |||||
| Swallows | |||||
| Swifts | |||||
| White Dove | 3 | 3 | 3 | 3 | |
| Wood Pigeon | 3 | 2 | 2 | 2+1* | 2 |
| Wren | 1 | 1 | |||
(Previous months results are here)
The numbers are the maximum number of a species we saw feeding at the same time (for our own records, we show newly fledged young with a * but we just send the grand total to the BTO). All the volunteers enter the numbers onto computer-readable cards which are sent back to the BTO each quarter.
What do these numbers tell us? Well, the statistics for a single garden don't give a balanced picture, of course. But from the combined results (representing now around 16,500 gardens) statistics are compiled which show how the populations of each species are affected by seasonal changes and other environmental factors.
Having said that, we have ourselves noticed some trends which have shown up nationally. These include an increase in visits from the delightful Long-tailed Tits and goldfinches, the decline in numbers of sparrows and starlings and relatively frequent appearances of Blackcaps (generally thought of as a summer bird) in winter.
More detailed surveys (perhaps including ringing) can then shed light on these trends: for example, the winter Blackcaps have been shown to be completely different birds to the summer ones: as one "shift" leave the British Isles for warmer places in Autumn, another "shift" arrives!
We've been recording our birds for five years now (three years statistics are on this site). It's brought us a lot of pleasure, and we've learnt a lot, too.
So... you're very welcome to keep an eye on the birds in our garden here, or better still - join in and watch your own!
To contact the BTO:
http://www.bto.org/gbw/index.htm
Also: For people interested in watching bird migration, and how it effects the summer and winter visitors to your garden visit http://www.bto.org/migwatch.
Garden Birdwatch
BTO
FREEPOST
The Nunnery
Thetford
Norfolk
IP24 2PU
For more information, see the Garden Birdwatch Home Page, or visit the BTO's main web site at: www.bto.org.