The UK's total wild bird population has declined by 13.7% since 1977, with numbers of some specialist species falling by two thirds.
Almost all broad species groups saw population declines over the last decade, with only woodland birds showing an increase between 2001 and 2011.
The most pronounced population changes took place between the late 1970s and early 1990s, according to figures covering 1970-2011 published by the Department for Environment, Food and Rural Affairs (DEFRA).
Numbers of farmland birds halved between 1977 and 1993, and specialist varieties are now only one third as numerous as they were 40 years ago.
A similar pattern emerges among woodland birds, where the total UK population fell by 30% between 1972 and 1995, and numbers of specialist species are now down by a similar margin on their 1970 total. Generalist woodland species, however, have grown in number.
A Defra Spokesperson said:
We're doing more than ever to protect our wildlife. The area of land protected or managed under woodland and agri-environment schemes is increasing, alongside this the condition of our protected sites is improving and the public are giving more of their time to conservation volunteering.
Our bird populations are a good indicator of the wider health of our environment and it is clear that more needs to be done to support the recovery of farmland and woodland birds. We all have a part to play, and we will continue to work with conservation groups and landowners to reverse this trend.
The seabird population boomed until 1999, but while it remains above its 1970 total, numbers have declined by over 10% in the last decade. Wintering water species have fared best in the period for which data is available, and are now almost twice as numerous as they were in 1976.
Bird population data was compiled in conjunction with the Royal Society for the Protection of Birds (RSPB), the British Trust for Ornithology (BTO) and the Joint Nature Conservation Committee (JNCC).
The full set of figures is below. What can you do with the data?