Bristle-thighed Curlews (Numenius tahitiensis, hereafter ‘curlews') breed only on low Arctic tundra in the southern Nulato Hills of the Yukon Delta National Wildlife Refuge (NWR) and on the Seward Peninsula, Alaska. Curlews use several distinct habitat types on the breeding grounds; however, quantified data of habitat use by curlews exist only for the Seward Peninsula. We investigated which available habitats on the breeding grounds were used most often by curlews in the Nulato Hills and compared availability with use to determine habitat selection using a land cover layer created in ArcGIS based on aerial photography and ground referenced locations. We also compared curlew habitat usage at our study site to habitats used on the Seward Peninsula. We used vegetation quadrats to determine plant composition within each habitat. We also determined percentage of habitat and plant composition within curlew territories. Curlews preferred shrub meadow tundra which consisted primarily of lichens (>50%), mixed with graminoid/herbaceous plants (∼13%) and few dwarf shrubs. Medium/tall shrub habitats, especially tall shrub thickets, were generally avoided by curlews on the ground, but the curlews were commonly observed flying and displaying over the shrubs. Low shrub tussock tundra and sedge wet meadows were occasionally used by curlews but not to the extent of shrub meadow tundra. The avoidance by curlews of areas with medium to tall shrubs was probably related to potential predation risks associated with reduced visibility in these habitats. Habitat selection was similar for both breeding populations of curlews, except curlews at our study site used shrub meadow tundra more frequently and low shrub tussock tundra and sedge wet meadow to a lesser degree than on the Seward Peninsula. Habitats differed in number of berry-producing plants. Berry-producing plants were predicted to be highest in the habitat curlews selected most (i.e., shrub meadow tundra); however, they were most abundant in habitats associated with tussocks.
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