Countryman Diary - June 2010
The decline of the House Sparrow
New research claims there is compelling evidence that the decline of house sparrows in Britain has been caused by intense predation from resurgent sparrowhawk populations.
Sparrowhawks were wiped out over much of Britain in the 1950s because of the effects of organochlorine pesticides, but since these were banned in the 1970s the number of sparrowhawks has quadrupled, and they started to colonise cities for the first time in the 1980s.
Urban sparrows were easily picked off because of their bold behaviour, which had developed in the absence of a significant threat from an aerial predator, the research reveals.
Dr Christopher Bell, an independent ecologist with over twenty-five years of experience studying bird behaviour, led the research. He says:
“The study shows that variation in the timing of the disappearance of sparrows from gardens across Britain can be explained by variation in the year that sparrowhawks began to be seen hunting birds in the same gardens.
“This overturns previous assumptions about the effects of predation on bird populations, and exposes flaws in studies apparently showing that sparrowhawk predation has no effect.“
Several puzzling aspects of sparrow decline are explained by this research. It reports that urban sparrows have tended to disappear from the more affluent districts of cities such as London, Bristol and Norwich, while continuing to thrive in less well-off areas, such as large council estates.
This is because the affluent parts of cities provide safe nesting places for sparrowhawks in the large gardens of grand houses, and in private grounds and restricted areas of parkland, whereas fewer nesting opportunities occur in poorer districts.
The results also explain why sparrow decline happened later in the cities than in the countryside. Sparrowhawks re-occupied most of the British countryside during the 1970s, coinciding with the decline of rural sparrow populations, but only started to move into urban areas in the late 1980s and 1990s, which coincides with urban sparrow declines.
The results emerging from this study are potentially embarrassing for those organisations involved in sparrow conservation which have consistently denied that increasing numbers of sparrowhawks and other predators can affect populations of wild birds. Instead they have promoted the idea that food shortage caused by changes in agriculture and urban development is behind sparrow decline.
Some conservation organisations have also promoted measures known as ‘agri-environment schemes’ to reverse the supposed effects of agricultural changes on wild birds. Farmers are now required to implement these measures to receive their subsidies under EU legislation.
The report says, however, that despite the fact that over two-thirds of farmland in England is now managed under agri-environment schemes, bird populations show no signs of recovery, suggesting that predators may be the real reason behind bird declines in the countryside.
More information on this research can be obtained at www.cpbell.co.uk, and on this study in particular at www.cpbell.co.uk/home/House-Sparrow-decline.
Support your local farm on Open Farm Sunday, 13th June (see below)
|
Open day on the farm
Open Farm Sunday, now in its fifth year, continues to help the public discover and understand the story behind their food, and the dedication and skill of farmers who produce it. Manager of Open Farm Sunday, Tom Allen-Stevens, explains: “Holding an Open Farm Sunday event is a very rewarding experience. Events needn’t be complicated to arrange and can be on a scale to suit the farmer and the farm. It’s a fantastic opportunity for farmers to engage with their local community and communicate the excellent work they do to produce the food we all eat.”
This year’s date is 13 June. For details visit www.farmsunday.org or telephone LEAF (Linking Environment And Farming) on 02476 413911.
Counting on Butterflies
The Big Butterfly Count is a major survey to assess the health of our environment. Organisers ned your help by making a fifteen-minute butterfly count during Save Our Butterflies Week from 24 July to 1 August. Records are welcome from anywhere; from parks and gardens, to fields and forest.
Butterflies are valuable indicators of the environment but many species are declining rapidly. The survey will help build up a picture of the changes taking place in our towns, cities and countryside.
The survey will be run by Butterfly Conservation, in association with Marks & Spencer as part of their commitments to encourage sustainable agriculture and help to protect the environment. Sir David Attenborough and Alan Titchmarsh have given their enthusiastic backing.
An identification chart and full details are available at the website www.bigbutterflycount.org.
All in Black and White
I hope you have been able to enjoy some lovely bluebell walks as I have in recent weeks
.
Unfortunately I didn’t find the time to visit Sussex, a stronghold for bluebells. But Sussex Wildlife Trust tell me they have growing concern that one of our most striking wildflower scenes may be under threat. Surprisingly rare in most of Europe and absent from the rest of the world, the native bluebell may face an uncertain future due to the long-term effects of climate change, and the loss and degradation of woodland habitats.
Spring flowers, including bluebells, currently have an advantage as they use the resources stored in their bulbs to start growing in the cold of winter or early spring. But with warmer springs, bluebells could lose this advantage, with other temperature-sensitive plants germinating earlier.
There may still be time to enjoy the sight of wild bluebells in Sussex this spring at one of the trust’s nature reserves, including Ebernoe Common and Burton Pond near Petworth in the west, Woods Mill near Henfield or Marline Woods near Hastings.
Visit www.sussexwt.org.uk/reserves/index.htm for more details.
Please remember, our native bluebell is protected and it is illegal to dig up the bulbs.
Competition Winners
Winners of the April crossword are Mrs C.A. Godfrey, Solihull - Mrs F Dick, Waterburn and Mr J Randall, Chesham, Bucks.
Thank you to all those who entered.
Paul Jackson
|
|
