Research from 250 gardens looks at birds using food and water provided.The number of different birds visiting the average feeding station rose from 16 in the 1970s to 23 in 2010.
Sightings of goldfinches, long-tailed tits, woodpigeons and greater spotted woodpeckers had risen most in the survey.
BTO head of garden ecology Mike Toms said different birds were visiting garden feeders more often for different reasons.
British Trust for Ornithology garden ecologist Tim Harrison said:
"Increased availability of specialist bird foods and feeders is pulling them into gardens."
BTO found up to half of householders feed birds in their garden with up to 60,000 tonnes of food a year used in all.