Birds as indicators
Wild bird populations are considered good indicators of ecosystem health, as birds occupy a range of habitats and are usually near the top of the food chain. The recent survey, a joint effort by the Department for Environment, Food and Rural Affairs (Defra), the RSPB and the British Trust for Ornithology, has shown that the number of birds foraging and nesting on farmland has decreased by 52% since 1970.
Martin Harper, conservation director for the RSPB, says, “The decline of the turtle dove is particularly worrying. This is a beautiful bird which has an iconic connection with the British rural landscape and we are only now starting to discover what is causing its population to plummet so alarmingly.”
Causes of the decline
One of the main reasons behind the decline in farmland birds is believed to be changes in farming practices, which are now more intensive and efficient. This has resulted in the loss of breeding habitat and a reduction in the amount of food available for birds. These declines come in spite of efforts to improve farming practices to reduce the impact they have on wildlife, and are potentially exacerbated by other factors, including disease and climate change.
The decline is not just limited to farmland birds, with numbers of woodland species down by around 20%. Populations of several species, including the willow warbler and spotted flycatcher, have suffered dramatic declines of over 70%. Although the causes of these declines are less clear, a lack of woodland management and overgrazing by deer are believed to be contributing factors.
Although the overall picture may be gloomy, populations of some species have increased, with the sparrowhawk and goldfinch, among others, increasing in number. Breeding seabird populations are also up by an overall 30% in the UK, though again, the picture is mixed with some species faring better than others.
Mr Harper says, “We should welcome the increase of some species, but we seem to be facing a growing number of threats.”
Read the full story in The Guardian – Turtle doves and partridges among wild birds in steep decline in Britain.
View the full findings of the survey – Wild Bird Populations in UK, 1970-2010.
Becky Moran, ARKive Species Text Author