Hopkins Marine Station Student Paper

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Title: Human recreation and its influence on coastal bird abundance, location, and behavior along the Pacific Grove rocky shore
Student Author(s): Herzig, Sarah
Faculty Advisor(s): Micheli, Fiorenza
Pages: 49
Location: Final papers Biology 175H
Date: June 2002
Abstract: The American Crow (Corvus brachyrhynchos), Western Gull (Larus occidentalis), and American Black Oystercatcher (Haematopus bachmani) are year-round residents in and near the rocky intertidal ecosystem of Pacific Grove, California. All three species are large mobile predators that serve important roles in structuring the rocky intertidal community. Due to the high abundance of human visitors along the Monterey Bay coastline, interaction between these birds and humans is inevitable. This study examined the effects of human presence on the spatial distribution and behavioral time budgeting of the aforementioned species. I found that humans were more abundant on weekends than weekdays, but no corresponding differences in abundance existed for birds. No significant correlation between bird location or behavioral time budget and human presence could be determined for any of the three species. When approached experimentally, resting birds of each species tended to take off at a farther distance from humans (lower tolerance) than did foraging birds, but these trends were not significant. Also, once disturbed, crows flew a significantly shorter distance than gulls and oystercatchers. These findings suggest that the abundance, behavior and location of these three species are not heavily influenced by human presence, but when disturbed the energetic cost to the bird may vary with species and behavior.