In response to accelerated timelines for the start of the California High-Speed Rail (CHSR) project and lack of access to some private property parcels, the CHSR Authority accepted a permitting strategy that assumed presence of multiple state and federal listed species that had the potential to occur within the construction footprint. This back-end heavy permitting approach led to thousands of pre-construction surveys, excavations, and trapping efforts that yielded species detections in limited areas of the construction footprint, with some permitted species not observed. The assumption of species presence required substantial habitat mitigation and as a result, the CHSR project is supporting species conservation in high-quality, occupied habitats. This presentation explores the outcome of a large-scale conservation benefit, which ultimately supported species such as the San Joaquin kit fox (Vulpes macrotis mutica) and Tipton kangaroo rat (Dipodomys nitratoides nitratoides) within their range, despite minimal risk of species take during CHSR project construction. Lessons learned from this approach now informs the Authority's evolving permitting strategy, helping to balance project delivery timelines with the use of presence-based data.