Scientists from RSPB, BirdLife International and the Czech Society for Ornithology analysed data for 378 out of 445 bird species native to countries in the EU and UK.
They found that between 1980 and 2017 there was an overall population decline of between 17% and 19%, equating to a loss of between 560 and 620 million individual birds.
A significant proportion of these losses are as a result of massive decreases in the more common and abundant bird species, the scientists said.
The largest drop in population is seen in the house sparrow, with 247 million fewer individuals, followed by yellow wagtail with 97 million, starling with 75 million, and skylark with 68 million fewer individuals.
When comparing populations by habitat, the highest total losses were seen amongst farmland and grassland birds.
The report states that “it is widely recognised that changes in farming practices driven by policy are responsible for a precipitous decline in wildlife”.
Long-distance migrants such as willow warbler and yellow wagtail have also declined proportionally more than other groups, as have shorebirds such as lapwing and dotterel.
Whilst much of the decline in bird numbers occurred during the 1980s and 1990s, in the last decade the rate has slowed, according to the authors of the report. In the EU, the Birds Directive and the Habitats Directive have provided legal protection to priority species and habitats and have been shown to benefit bird species, as well as enhancing habitat protection, they said.
This has led to population increase in seven species of birds of prey following increased protection and reductions in pesticides and persecution, as well as from the introduction of targeted recovery projects.
“Without the introduction of these directives, there is little doubt that declines in many species would have been much worse,” the report found.
Fiona Burns, RSPB senior conservation scientist and lead author of the study, said: “Next year the United Nations Convention of Biological Diversity will be meeting to discuss the future of our global biodiversity, and create a framework which calls for increasing conservation efforts to be targeted towards preventing extinctions and recovering species abundance.
"Our study is a wake-up call to the very real threat of extinctions and of a Silent Spring, and we are fully supportive of ensuring a strong framework which puts conservation front and centre of any global plans.”