Feeding the birds in the back garden has boosted the populations of an array of species that flock to them, a scientific study suggests.
Providing a growing number of feeders and different types of food has also increased the variety of species visiting gardens over the past 40 years, the research found.
A practice that began with kitchen scraps on home-made table feeders has boomed into an estimated £200 million-£300 million a year industry in Britain, with half of British homeowners putting out the likes of seed and fat balls for birds.
Researchers from the British Trust for Ornithology (BTO) examined bird food adverts to track the growing popularity of feeding wild birds over the past 40 years, with a rising number of products and a wider range of foods.
Specialist foods such as sunflower hearts and fat balls first appeared in the 1990s as companies backed by conservationists deliberately increased the range of products to attract more species.
They also looked at 40 years of data from the Garden Bird Feeding Survey, run by the BTO, and found an increase in the range of birds using garden bird feeders since the 1970s.
While garden bird feeders in the 1970s were dominated by two species, house sparrows and starlings, today a much broader range of species is commonly seen taking advantage of the variety of food on offer.
For example, less than a fifth of those taking part in the Garden Bird Feeding Survey in 1973 reported seeing goldfinches and wood pigeons, but that figure has jumped to more than 80%, the BTO said.
The provision of bird food is estimated to be enough to sustain up to 196 million birds, more than the combined total population of many common garden species.
It helps them survive the winter, put them in better physical condition and helps them breed more successfully.
The study found that populations of birds that used feeders in urban areas increased significantly over four decades, while those that did not remained unchanged on average.
Lead author Dr Kate Plummer, research ecologist at BTO, said: “We now know that garden bird feeding is one of many important environmental factors affecting British bird numbers.
“Regular visits to garden feeders in urban areas appear to have led to population growth across more than 30 different bird species, while there has been no change in the average population sizes of birds that don’t visit feeders.
“It is fascinating to discover how this seemingly small-scale hobby is in fact restructuring bird communities across large spatial scales.”
The research is published in Nature Communications.