eWestern BirdsThe Quarterly Journal of Western Field Ornithologists
Vol. 45, No. 3
Western Field Ornithologists
First Successful Nesting of Swainson’s Hawk in Santa Clara County, California, since the 1800s
Ryan A. Phillips, William G. Bousman, Mike Rogers, Ryan Bourbour, Breanna Martinico, and Michael Mammoser
ABSTRACT: We documented successful nesting of a pair of Swainson’s Hawks (Buteo swainsoni) over two consecutive years (2013 and 2014) in Coyote Valley, California, which represents the species’ first nesting in Santa Clara County since 1894 and a range expansion of approximately 60 km from the Central Valley into the species’ historic range. It confirms that there is habitat in Santa Clara County for breeding Swainson’s Hawks, which has implications for conservation. Expansion of this species’ breeding, in recent years, has been documented in other counties within the central and northern Coast Ranges of California, including San Benito, Napa, and Sonoma, suggesting that efforts toward Swainson’s Hawk conservation in California have allowed this species to recolonize some of its historical breeding range, or that Swainson’s Hawk may be adapting to new areas of natural or human-modified habitats.