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Abstract:
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Examining the spatial ecology of waterbirds is essential for the conservation and management of wetland areas. I studied the space use (movements and home ranges) of radio-marked female American avocets (Recurvirostra americana) in South San Francisco Bay, California. Direct visual observations were used to determine the breeding stage (pre-incubation, incubation, brood-rearing, post-breeding) of marked avocets.
Linear movements, home ranges, core areas, and average distances of avocets from nests varied significantly among stages. Post-breeding space use metrics were the greatest, followed by pre-incubation, incubation, and brood-rearing. The majority of avocet nest locations (93%) were within the pre-incubation core area boundaries, whereas 36% of nests were within post-breeding core areas. Distance between future nest sites and daily location decreased significantly with number of days prior to incubation.
The differences in home ranges, core areas, and movements between the pre-incubation and post-breeding stages suggest space use of female avocets may be influenced by breeding activities. Average distance from nest during the pre-incubation stage suggests that avocets may be prospecting future nest sites up to three
weeks prior to nesting. In a highly managed estuary like the San Francisco Bay, natural resources managers can utilize spatial data and implement conservation strategies that maximize the potential for continued survival of American avocets and other breeding waterbirds. |
