Abbotskerswell Parish Council went to the High Court to fight for the survival of greater horseshoe bats, one of the rarest bats found in Britain.
The council claimed Teignbridge District Council’s local plan could be the death knell for the bats in the area.
The local plan at the centre of the case makes provision for around 5,000 new homes in the Teignbridge Council area.
However, Abbotskerswell Parish Council asked the judge to quash key policies of the plan.
It argued that the housing plan raised "fundamental concerns" for the protection of rare wildlife in the area.
The plan, it claimed, had been adopted in a way that failed to ensure the necessary protection for the South Hams Special Area of Conservation (SAC). This is a European protected site that hosts around 30 per cent of the UK population of greater horseshoe bats.
Jenny Wigley, representing the parish council, told the judge that the bats use the wider countryside of South Devon for commuting, foraging, roosting and mating, but that a large number of newly allocated houses and employment buildings could lie within or very close to "strategic flyways" and "sustenance zones".
She argued that Teignbridge Council failed to comply with its obligations under EU law.
However, Michael Bedford argued on behalf of the local planning authority that there had been no legal error on its part, and said that quashing the policies would prejudice proper planning in its area.
After two days of legal argument Mrs Justice Lang has already indicated that when she gives her judgment she will come down on the side of the district council.
Because of the complexity of the case the judge has reserved judgment and will give her reasons for the ruling in writing at a later date.
Abbotskerswell Parish Council v Teignbridge District Council. Case Number: CO/2792/2014