Coastal pasture use by Long-billed Curlews at the northern extent of their non-breeding range

Abstract

The Long-billed Curlew (Numenius americanus), a declining species of Nearctic shorebird, winters as far north as Humboldt Bay, California, where it feeds principally in intertidal habitats but shifts to pastures with onset of seasonal rains. We studied variation in abundance and behavior of curlews in coastal pastures in relation to environmental variation that may influence the profitability of intertidal and pasture habitats as foraging sites. Curlews occurred in greater abundance in pastures during morning hours, when intertidal habitats were exposed for longer intervals during daylight hours, and coincident with greater rainfall. While using pastures, most curlews fed, and this proportion varied positively with intervals of lower tides in intertidal habitats. Pastures provide important foraging habitat for approximately one third of the 200–300 curlews wintering at Humboldt Bay, especially when inclement weather makes foraging in intertidal habitats difficult and increases food availability in pastures.