A developer aiming to transform a 300-acre site in the Verdugo Mountains into a luxury housing development is suing a group of activists for trespassing onto the property. The group says it is gathering evidence that the land should be preserved to protect endangered species.

Nevada-based Whitebird plans to build 221 homes on a rugged hillside in the Sunland-Tujunga neighborhood on the northern edge of Los Angeles. The development was originally approved by the Los Angeles City Council in 2005 and has a 20-year window of completion that runs through October 2026.

Local groups have pushed back against the project during the past two decades, with concerns about bringing traffic to the rural area and the safety of building homes in the fire-prone mountains. Whitebird scaled down the original project from 900 to 300 acres, donating the remaining 600 acres to be preserved as open space.