Decade of surveys tells story of change
Monday 20th September 2010
Better bird-seed recipes, newly-gained skills and home make-overs are changing the types of birds seen most often in West Country gardens, according to the final report from one of the UK’s biggest ‘citizen science’ projects – the decade-long Bristol Bird Watch.
Since the winter bird study was launched in 1999/2000 by Avon Wildlife Trust, Bristol City Council and Bristol Naturalists’ Society, more than 1,000 people a year have signed up to record the bird species they see in their gardens between October and March.
The project is ending now - to make way for another, on house sparrows - so its latest, report (published this week) looks back not only at which birds were spotted during winter 2009/2010 but also at the changes revealed by 10 years of record-keeping in and around Bristol , Bath and neighbouring parts of North Somerset and South Gloucestershire.
Project spokesman, Steve Micklewright, of Avon Wildlife Trust, says: “The most telling story from the figures is of how human actions impact on local wildlife, creating winners and losers. For instance, adding Nyger to bird food mixes has helped goldfinch numbers to rise significantly, and many more gardens are seeing the tiny and beautiful long-tailed tit now that the species has learned how to use fat-balls and peanut feeders.”
But, he adds: “Birds can also suffer from the unintended consequences of what people do. An example is that sightings of house sparrows and starlings have become increasingly uneven geographically during the survey period and evidence is emerging of a match to where householders can afford property make-overs - introducing paved patios, decking, cladding and so on which reduce feeding and roosting opportunities. As a result, we want to look at this more closely through the new ‘citizen science’ survey which will succeed Bristol Bird Watch - Wild Sparrows – www.wildsparrows.org.uk. ”
Another long-term finding confirms that large numbers of blackcap now prefer to winter in the West than in Spain - a population in Germany having learned that, from Britain, they return to their nesting sites sooner and fitter than Spain-based rivals.”
Data analyst Richard Bland, of Bristol Naturalists’ Society, says garden sightings of woodpigeon, dunnocks, jackdaws and jays have also increased in the past decade but that there has been an as-yet unexplained decline in starlings. “Starlings still occur in 70% of the gardens surveyed but numbers overall are still falling year on year.”
Blackbirds, robins and blue tits remain a constant at the top of the 10-year chart, followed in slightly changing annual order by magpies, wood pigeons, collared doves, great tits, wren, chaffinch and house sparrow. The highest number of different species recorded since Bristol Bird Watch began was 61 in 2008/09, with the average per garden getting around 21.5 species and more than a third welcoming 25 species or more.
Among the rarest sightings of the decade have been linnet, yellow hammer, tree creeper, reed bunting, a little egret and, for two years running near Clevedon, parakeet.
Freezing temperatures and snow from December to February 2009/2010 saw nearly all local gardens become busier with birds with especially striking results for some watchers in January.
Richard Bland relates: “With deep snow covering fields across the country, thousands of Redwings and Fieldfares flocked into gardens to replace their usual diet of invertebrates with berries and apples to avoid starvation. Most returned to the fields as soon as the thaw came but the very cold weather also brought more song thrushes into gardens and a tripling of blackbird sightings.”
The report concludes with thanks to everyone who has supported the survey during the past years and a reminder to gardeners.
Steve Micklewright summed it up, saying: “Bristol Bird Watch has been a remarkable example of Citizen Science, involving several thousand volunteers from all walks of life, including several who have taken part throughout. Their feedback is it has been a hugely enjoyable and meaningful experience which has brought them closer to nature. Even so, we are deeply grateful to each and every one of them. The data-sets not only provide invaluable insights for wildlife scientists and environment planners but also remind us of the vital role gardeners and gardens play in helping birds to survive a winter.”
Bristol Bird Watch’s successor project – monitoring house sparrows – is already underway but new volunteers are welcome. To find out more, please contact Avon Wildlife Trust on 0117 917 7270 or visit http://www.wildsparrows.org.uk/