It occurs to me that my annual Wimbledon bird list is not organised in the best way for science. While covering the championships for this newspaper, I have made a count of 11 species, to wit (though there were no owls, alas) feral pigeon, pied wagtail, swift, black-headed gull, mallard, blackbird, carrion crow, magpie, wood pigeon, herring gull, starling. (A reader, Ricky East, contacted me to say there was a nest of pied wagtails by gangway 9, No 1 Court, but, alas, they had gone before I went to look.) There are many reasons why my data is useless. For a start, I have recorded numbers of species, like a birder, rather than numbers of individual birds, like an ecologist. The second is that my records reflect other things than the presence of birds.
I haven’t recorded many species this year, but that’s because I have spent a lot of time under the roof. For some reason all the matches I have covered this year have been on Centre Court, which gives a limited view of the sky and no trees whatsoever. It’s been a pretty hectic Wimbledon, so I haven’t spent much time in the open refreshment area. My data tells you what sort of Wimbledon I’ve been having, not what’s happening with Britain’s birds.
So I walked across the road to Wimbledon Park, there to meet with a real ecologist, Dave Dawson, who among many other things is a former council member of London Wildlife Trust and has given great assistance to that important organisation. He has been surveying Wimbledon Park for a quarter of a century — and he has organised his Wimbledon material rather better than I have mine.
The numbers game
Advertisement
Wimbledon Park is a quintessential urban park. It was laid out by Capability Brown for the rural retreat of the Spencer family, but there are not many traces of grandeur left. It’s got trees, it’s got a couple of scraps of woodland, it’s got open grass, it’s got a fairly hefty lake where anglers and boaters compete for mastery. Over the past fortnight, it’s been mostly a car park and site of the Wimbledon queue.
It’s not special. It’s not like the London Wetland Centre, which I visited last week, full of breeding terns and lapwings and jumping with bitterns in the winter. Its ordinariness is rather the point. Dave has invented a gloriously simple research tool called the standard walk and he has been doing it every month across Wimbledon Park for 25 years. He has counted individuals as well as numbers of species; he has also collected and organised botanical information.
And if you do this in an organised and thoughtful way, patterns emerge, patterns that can have local, national and even global significance. He showed me a series of graphs and bar charts, the distillation of all those hours, all those paces, all those notes. You have to love numbers as an ecologist, almost as much as a physicist does. The understanding of the beauty of numbers is essential, something that requires stern mental effort from a journalist who finds doing his expenses enough to make his nose bleed.
Dave’s accumulated data shows that some birds have declined, some have increased, some have remained steady. Ring-necked parakeets, now common in southwest London, have increased in Wimbledon Park. People fear that by monopolising potential nest holes, they would affect the numbers of nuthatches and great spotted woodpeckers; the data indicates that this is not the case.
His numbers for water birds, especially cormorants and herons, show some sharp and unexpected declines. Possibly (can I say “probably”?) this is down to hostile action from fishermen. The golf course had a cull of Canada geese last year, one that left the park full of wounded and dying birds; not a good episode.
Advertisement
Deciding point
It was as we passed the lake that I saw a house sparrow and pointed it out, not without satisfaction, because sparrows are the most interesting aspects of Dave’s research. When he began he was averaging 80 sparrows with each walk. This has gone down to an average of one.
This terrible decline has sneaked up on most of the world, but not on Dave. Sparrows have not been surveyed systematically elsewhere until comparatively recently, when the decline was already under way. They were on the pest schedule and scarcely considered birds. Dave’s figures demonstrate the long-term and catastrophic nature of the decline.
There is now research into this decline: some suggest that food shortages are the problem, particularly at breeding time, and there are experiments involving artificial feeding. Dave points to an increase in sparrowhawks and suspects that their presence may inhibit sparrows and limit the places where they can feed.
Advertisement
That’s speculation. Numbers are facts. Their organisation has its own beauty: they are essential to understanding the world and what we are doing to it.