Save Our Suffolk Swifts said 504 boxes were used at 138 different locations in Suffolk last year, up from 379 boxes at 85 locations in 2024 and 263 in 79 places in 2023.
The boxes are located at people’s homes and at various schools, churches and other elevated buildings across the county, from Bury St Edmunds to Leiston.
“There’s so many people who have put so much effort into installing nest boxes, so it is fantastic and very exciting,” said the group’s Eddie Bathgate.
“We’ve now got 500 boxes showing signs of swift activity in the county – that’s up from one or two back in 2011, so that’s an enormous increase.
“There’s a lot of very happy people around Suffolk who are now able to watch swifts, and their daring summer displays.”