WILDLIFE Trust volunteers lost count as families poured into the annual open day at Deeping Lakes Nature Reserve on Sunday.
Children enjoyed willow weaving and pond-dipping for water creatures in the lake and there were nature walks as well as teas and refreshments.
It was one of the best-attended open days at the former gravel pit, which is open to the public at all times.
Chris Bladon, of Lincolnshire Wildlife Trust, said: “It was one of the best days we’ve held but we had no way of keeping exact count.
“We’re expecting to have made more than the £100 or so we usually raise, but the main point is to make everyone aware that the reserve is here for them to enjoy.
“We always hold it about this time of year when the dragonflies are out in force.”