eWestern Birds

The Importance of Agriculture to Long-billed Curlews in California’s Central Valley in fall

W. David Shuford, Gary W. Page, Gary M. Langham, and Catherine M. Hickey

ABSTRACT: The Long-billed Curlew (Numenius americanus)—a large shorebird of continental conservation concern—is a migrant and winter resident in California’s Central Valley. The size of the curlew’s North American breeding population has been estimated recently, but little is known about its abundance and habitat needs at migratory stopovers and wintering areas. Following two broad-scale surveys of the curlew in the central and southern portions of the Central Valley in fall in 2007 and 2008, we coordinated a survey of it throughout the valley in August 2009, recording 20,469 curlews in 195 flocks. On all three surveys, during this otherwise arid season, curlews were found primarily in irrigated alfalfa and irrigated pasture. There was a strong, positive relationship between curlew abundance by subregion of the Central Valley and the subregion’s proportion of the entire valley’s acreage of both alfalfa and irrigated pasture. Identifying the habitat features important to curlews at both fine and landscape scales, documenting the birds’ movements (within and between seasons) in the Central Valley, and monitoring their populations is needed to aid in the conservation of this shorebird at risk.

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