Analysis of long-billed curlew (Numenius americanus) distributions at three spatial scales

I examined the low tide spatial distributions (uniform, random, aggregated) of Long-billed Curlews (Numenius americanus) at three spatial scales, within individual home ranges ( 8 ha), within an estuary ( 50 ha), and across Humboldt Bay ( 5000 ha). For eight individual curlews, space use differed in home range size (1.3 — 7.5 ha) and distance moved over 2-hrs (1.1 — 2.8 kin). Spatial distribution of curlew locations within home ranges (recorded at 2-min intervals) was predominantly (74%) even. Distributions of curlew locations within smaller home ranges were more even than curlews using larger home ranges. Within the Elk River Estuary, number of curlews using intertidal habitats (May 1999 — April 2000) at low tide 0.3 m) ranged from 1 — 20. Dispersion patterns of curlews in the estuary were most often (73%) uniform during summer surveys and were significantly and inversely related to curlew abundance. Across Humboldt Bay, curlews using intertidal habitats at low tide concentrated in certain areas producing significantly aggregated distributions on six occasions. Number of curlews present ranged from 168 — 301. Variations in distributions across spatial scales were possibly a response to variations in food distribution. Recognizing a species' spatial distribution is the first step in understanding a species' ecology and can be used to predict effects of potential habitat loss.