Taylor Wimpey is set to spend £500,000 on a bridge for dormice as part of a 525-home development in Somerset.
The proposed Crewkerne scheme has been held up for three years because of concerns about its impact on the local dormouse population.
The development, between the A30 to Yeovil and the A356 to Dorchester, will also include employment buildings, a primary school, community facilities, playing fields, a link road, and highway improvements.
Taylor Wimpey is proposing to construct a bridge across the link road to help preserve the habitat of the rodents, as part of the Crewkerne Dormouse Mitigation Strategy, created by the house builder and wildlife specialist Ecology Solutions. It would feature two-metre-high walls and cost around £500,000.
The developer hopes the bridge will persuade local planners to give the planning green light for the scheme. Outline permission was granted in 2007.
Crewkerne town councillor Mike Best told the Western Gazette: "This has been going on for many years and if an agreement can be reached on a positive strategy, then it is good news at last.
"The dormouse situation is a big issue. They make things more tricky.
"If it had been badgers or foxes it would have been a lot easier because you can build a tunnel and they can go underground."