Scientists estimate the number of nesting birds has plummeted from 210 million in 1966 to 166 million today. The shocking statistics are contained in the report, charting the ups and downs of Britain’s bird populations.
There have been winners as well as losers.
One of the biggest losers is the House Sparrow, with a population of around 20 million fewer than in 1966, when the first reliable all-species bird-monitoring scheme was conducted – despite numbers starting to increase in the last 10 years.
Some explanations can be found in the changes in land use while management of the coastal waters are believed to have contributed to the losses. In some cases, birds have found it difficult to locate suitable places to nest, or to forage for food in the summer or winter.
Cold weather has impacted, too, and is believed to have had a startling effect on the Winter Wren. Still the UK’s most numerous bird, an average of 835 wrens have been lost each day since 2000. The reasons behind the house sparrow decline are still not fully understood.
The populations of farmland bird species is now less than half what it was in 1970, according to the report, which draws on data from leading organisations including the RSPB, the British Trust for Ornithology (BTO), the Wildfowl and Wetlands Trust (WWT) and BirdLife International, as well as government agencies.
Experts say breeding birds have vanished from the British countryside at an average rate of one pair every minute.
Mark Eaton, an RSPB scientist, who worked on the report and says of it: “It is shocking to think we’ve lost one in five of the individual birds that we had in the 1960s, especially when you think that the 44 million birds we have lost since 1966 is equivalent to the current adult human population of England and Wales.”
The Eurasian Chaffinch has increased at a rate of 150 individuals a day over the period.
The Eurasian Collared-dove, whose numbers were very low as the species only started nesting in the UK in 1955, has seen its numbers explode to around 1 million pairs.
The closely related European Turtle-dove, which in 1966 was widespread with around 140,000 breeding pairs, however, has been decimated. Today there are thought to be just 14,000 nesting pairs.
The report, which also examined bird populations of the UK’s overseas territories, highlighted concern over the Northern Rockhopper Penguin, found on the remote south Atlantic volcanic islands of Tristan da Cunha and Gough Island. Once to be found in their millions, the numbers of the distinctive penguins have crashed, with food resources, disease and predation all being possible causes.