Type: report

Article abstract: The overall purpose of this document is to identify and prioritize conservation and management needs for BUOW in San Diego County to support a coordinated and evidence-based species recovery strategy. This document addresses the numerous existing threats to BUOW and provides an integrated tactical plan to achieve a stable and viable population in this region. The plan focuses on establishing new areas for recovery of BUOW to lower the risk of local extinction and increase overall population size and stability. Section 2 of this report assesses the current status of the Otay BUOW population, as the last remaining breeding population in the County, using a population viability analysis (PVA). In PVA, population trajectory over 50-100 years is simulated based on field data for demographic rates in the targeted population. PVA provides a quantitative prediction about future trends and extinction probability, while also indicating which demographic rates (e.g. mortality, reproduction) are most influential in driving population changes. Section 3 of the report summarizes study findings on best management strategies, organized by management situations. It includes detailed treatments of the key factors for establishing new breeding sites and optimal relocation techniques for both California ground squirrels and BUOW. For example, the 2013 MSP approach for immediate interim management measures included artificial burrows and habitat enhancement on conserved lands in the vicinity of Otay Mesa/Otay River Valley to provide suitable habitat for owls that may be displaced by development. This Conservation and Management Plan supports those objectives by detailing the siting of artificial burrows, presenting improvements on existing burrow design, and identifying the level of annual maintenance required to keep artificial burrows functional and available to breeding owls. Section 4 of this report details regional habitat suitability modeling begun in 2015, and followed up with rapid assessments conducted in 2016-2017. The rapid assessments included a suite of standardized fine- scale field surveys of prey (small mammal) availability, predator pressure, vegetation, and soil texture. These efforts were designed to identify priority sites for future species management, and ten sites have been evaluated to date. In Section 5, the suitability results from both the regional modeling and the rapid assessments are reported and discussed by site.