On Friday 24th March 2012 I attended the Stone group of Staffordshire Wildlife Trust to hear a very interesting talk by Gerald Gittens of the British Trust for Ornithology (BTO). I found out about this talk via twitter, as I follow @bitofstone. The event attracted an audience of about 40.
Gerald told us about the work of the BTO which focuses on scientific surveys and complements the work of other organisations such as the RSPB and the JNCC. Such work, carried out largely by volunteers, is of interest not only to the bird watching public but also to wildlife and conservation groups and government. Gerald described three core types of survey the BTO carries out; the breeding bird survey, the garden bird watch and the wetland bird survey.
The breeding bird survey involves many randomly defined 1km by 1km squares each allocated to a volunteer. The volunteer will perform bird counts along each 200m of a walk along two defined 1km stretches within their square. These counts are carried out in the early morning during the spring. The numbers of different species seen or heard within certain distances from the route or flying overhead are recorded.
The garden bird watch is carried out by other volunteers who, every week all year round, note the maximum number of each species observed in their gardens.
The wetland bird survey involves volunteers counting species at many specific locations clustered around the coast, estuaries and other wetland areas.
All the data are statistically analysed and reports are produced of the results. Gerald showed us examples of the tables and graphs produced, which as a scientist kept me very happy. Plus maps, I’m very fond of maps too.
The graphs showed how garden birds are observed in larger numbers during the winter months and smaller numbers during the summer, so graphs over many years showed spikes but an overall trend on top of that. Some examples given included buzzards, the numbers of which have risen tremendously over the last 15 years, cuckoos which have markedly decreased, sparrows which are also on the decline and goldfinches which are on the rise. A drop in goldcrest numbers was also reported. I can only assume numbers started very high as I encounter large numbers of them in many locations when I’m out walking, difficult to see but distinctive by their high pitched call. As well as trends, the prevalence of various bird species was also shown. For example in garden bird watching, blackbirds are seen in almost all gardens but some species such as yellowhammers are very rare. This matches my experience, I have never seen a yellowhammer in my garden. I know where to find them though in the countryside to the West of Stone and Trentham, along with very many other species as well.
The BTO are able to accurately report on bird numbers and locations because of having a large number of well distributed areas from which to extrapolate. Comparisons can also be made with similar surveys in other parts of the world. For example in other parts of Europe the cuckoo is not decreasing, in some areas it is increasing. It seems that it is tending not to stop off in Britain on its migratory route. Finding reasons for the observed trends is rather more difficult than measuring them and subject to a bit more guesswork. The increase in buzzards for example could be attributed to less use of pesticides allowing greater availability of their food chain, but a decrease in kestrels is not easy to explain. Garden bird numbers can be affected by disease actually spread due to visits to bird tables. This serves as a reminder to us all to keep our bird feeders clean to avoid an adverse effect on the very wildlife we are trying to encourage and enjoy watching.
Gerald told us that the wetland bird surveys were most popular amongst volunteers and the breeding bird surveys were the hardest to find volunteers for. That surprised me a little. Garden birds I think have a greater cuteness factor than water birds. But perhaps I think this way because of living in Staffordshire. I expect if I lived on the coast I would be much more interested in the water birds around me. The survey that sounded to me the most interesting to do is the breeding bird survey, because it allows you to get to know an area near you very well. Also, it combines looking for birds with a walk, albeit a very short one.
I would like to thank all concerned for putting on a very good event.
I am no expert on birds, I’m just an ordinary person with a good deal of interest in most things around me. I have the usual garden birds; blackbirds, great tits, blue tits, robins, sparrows, a woodpigeon or two, the odd magpie and recently the occasional chaffinch. But my interest has been enhanced since I got a seed feeder and more recently a niger seed feeder, pretty much by ‘accident’ as I dislike shopping and happened across them rather than set out to buy them. I hoped the niger feeder, purchased at the Wolseley centre, might encourage goldfinches which are pretty in colours and song, but I was prepared for maybe having to wait many months to see them. As it was redpolls appeared within a week, I have never seen these so close up before. The male doesn’t visit as often as the two females, which appear daily. I thought it doesn’t matter if I never get goldfinches because the redpolls are so nice anyway. But then two goldfinches appeared on Friday morning. One flapped around nervously and didn’t stay very long but the other stayed a good while. I have not seen them since but they know where my feeder is now so I think they will return again sometime. That’s new redpolls and goldfinches into my garden within two weeks of buying the niger feeder. I’m very pleased.
Relevant on twitter: @Nicky_Davis_ @StaffsWildlife @_BTO @Natures_Voice @bitofstone