27/04/2010
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Garden bird winners and losers in 2009

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The latest results from the BTO's Garden BirdWatch survey have just been published and reveal the garden-bird winners and losers in 2009. The definite winner of 2009 was Goldfinch, up by 78%, whilst House Sparrow was the distinct loser, falling by a further 15%.

Goldfinch
Goldfinch, Stodmarsh NNR, Kent (Photo: Mike Gould)

The results also reveal marked seasonal differences in the use of gardens by Goldfinches, with occurrence highest in late winter when food in the wider countryside is depleted. However, intriguingly, there is a secondary peak during egg-laying (around week 24). This secondary peak is likely to be caused by an influx of birds that have failed to secure a breeding territory in the wider countryside, or breeding females using gardens to build up their reserves for egg-laying. Interestingly, this secondary peak appeared more pronounced in 2009 compared to the long-term average.


Seasonal trend in reporting rate of Goldfinches in GBW gardens.

Another winner was Long-tailed Tit, reported in 30% more gardens, tumbling through bushes in its feeding flocks. Woodpigeons increased by 26%, though these are less popular with householders owing to their propensity to 'hoover up' food. The sociable Jackdaw increased by 19%, and the striking Great Spotted Woodpecker was up by 15%.

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The winners and losers of 2009, with changes compared to the long-term average (1995 to 2008).

However, it was not all good news; 2009 had its losers too. The precipitous declines of Song Thrush, Starling and House Sparrow were still evident in 2009, recorded in 22%, 19% and 15% fewer gardens compared with the long-term average, respectively. Alarmingly, however, comparable declines were also seen in Wren and Greenfinch — down by 20% and 16%. The diminutive Wren is likely to have struggled in the relatively harsh winter of 2008/09 and could also have been affected this last hard winter, so tracking its numbers over the forthcoming months is essential. In Greenfinches, the slow but steady decline seen since 2006 may be due in part to an increase in the disease Trichomonosis.

House Sparrow
House Sparrow, Ipswich, Suffolk (Photo: Brian Holland)

BTO Garden BirdWatch is a unique survey, running every week throughout the year. This means that seasonal differences — some of which are subtle, some huge — in the use of gardens by birds are revealed. For example, while Goldfinches increased by 78% in 2009 compared with the long-term average, this figure varied seasonally, peaking at 103% in mid-summer. Conversely, the decline of Song Thrushes in gardens was most pronounced during the same period, down by 35% against the long-term summer average.

Dr Tim Harrison, BTO Garden BirdWatch, commented: "The use of gardens by Goldfinches changed markedly throughout 2009. However, in the summer there was a particularly pronounced increase in their occurrence in gardens. This suggests that Goldfinches had a productive breeding season and that juvenile Goldfinches moved into gardens for an easy meal."

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He added: "Remarkably, Woodpigeons were recorded in a greater percentage of gardens than Robins in the spring and summer of 2009! This is indicative of how the Woodpigeon population has exploded in recent years. However, there are concerns about the status of other species such as Wren and Greenfinch. Thankfully, thousands of BTO Garden BirdWatchers will monitor their fortunes closely over the coming year."

The BTO Garden BirdWatch is the only nationwide survey of garden birds to run weekly throughout the year, providing important information on how birds use gardens, and how this use changes over time. Currently, some 15,000 people take part in the project. The project is funded by participants' contributions and is the largest year-round survey of garden birds in the world. For more information see www.bto.org/gbw

For more information about BTO Garden BirdWatch and for a free enquiry pack please telephone 01842 750050 and ask for the GBW team, email gbw@bto.org or write to GBW, BTO, The Nunnery, Thetford, Norfolk, IP24 2PU.

Written by: BTO