Turtle doves have seen numbers plummet as farmland bird populations reached new record lows, official figures have shown.
Numbers of 19 species of bird which breed or feed on farmland are now half what they were when records began in 1970, according to figures published by the Environment Department (Defra).
Most of the reductions occurred between the late 1970s and early 1990s but numbers fell by more than 9% in the five years to 2009, the statistics revealed.
Turtle doves, a traditional symbol of love and one of the gifts in the song The 12 Days of Christmas, have seen populations fall by more than 90% since the 1970s and by more than half in the past five years alone.
The RSPB said turtle doves, a migratory species which relies on seed rich wildflowers and weeds in the countryside, declined by 21% between 2009 and 2010 and there were now only seven birds for every 100 there were in 1970.
The long-term declines in farmland bird numbers are largely driven by falling populations of "specialist" species who are restricted to or highly dependent on farming land.
Corn buntings and grey partridges have seen numbers drop by more than 90% over 40 years in the face of changes in farming practices, although two specialist farmland bird species - the stock dove and goldfinches - have seen numbers double.
Generalist species have fared better, with woodpigeons and jackdaws doubling in number, but yellow wagtails have declined by more than 70% since the 1970s.
Martin Harper, RSPB conservation director, said: "These official figures once again show that farmland wildlife is struggling in our countryside.
"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."