ASSESSING OSPREY NESTING HABITS, SUCCESS, AND PRODUCTIVITY IN HUMBOLDT BAY USING THE MAYFIELD METHOD FOR NEST SUCCESS MODELING
Patricia Torres1, Micaela Szykman-Gunther1, Rene Torres2.
1Humboldt State University, Arcata, CA, 2California State University Northridge, Northridge, CA.
Understanding the reproductive biology of sensitive species of wildlife is essential to making well- informed management decisions, especially in a highly urbanized setting. An assessment of osprey (Pandion haliaetus) nesting success and productivity has not been conducted in the Humboldt Bay area of northern California in recent decades, following steep population declines in the 1950s associated with the widespread use of chlorinated hydrocarbon pesticides such as DDT. Our goals are to better understand how osprey have adapted to an increasingly urbanized landscape by studying the local population's nesting success and productivity as well as observing nest location and structure. With this information, we will determine if current breeding pairs of osprey are producing enough young to maintain a stable population in this region. Our study was conducted by surveying on foot and using local knowledge to locate and map osprey nests along Humboldt Bay. We will model nest success using the Mayfield method, a method known to be effective in reducing bias associated with sampling error. Observations suggest that nesting success and productivity of osprey will be stable as many breeding pairs reared young in close proximity to human activity and in various manmade structures. We also observed competition with local gull species, which reared young on abandoned osprey nests. High nesting success and productivity will be indicative of a species with versatile nesting habits. As urbanization continues to expand throughout the U.S. and the world, studying how species adapt to these changes is an integral element in conservation.