Type: journal article

Article abstract: Burrowing Owl (Athene cunicularia) populations in San Diego County appear to have decreased through the early 1900s in conjunction with human population growth and concomitant habitat loss. By the late 1970s/early 1980s, there were perhaps 250-300 pairs left, but as of 2003 the population had been reduced to no more than 25-30 resident pairs (note: recent surveys revealed additional owls suggesting that there were, at most, 46 pairs in the county as of 2007). Primary threats to the remaining small Burrowing Owl population in San Diego County are reduced habitat suitability and fragmentation of remaining suitable habitat; conflicts with management of listed species, especially the California Least Tern (Sterna antillarum browni) and Western Snowy Plover (Charadrius alexandrinus nivosus); and human disturbance (including their pets and vehicles). In addition, predators, prey abundance and availability, and colony size are likely factors influencing population dynamics, the relative importance of which are difficult to characterize. Given county owl population declines and current threats, a comprehensive management program is essential to protect remaining habitat and owls. If such a plan, or similar action, is not implemented soon, extirpation of the Burrowing Owl in San Diego County seems imminent.