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Tracking Ospreys in the Age of Silicon

Dr. Richard (Rob) Bierregaard – Tracking Ospreys in the Age of Silicon: Migration, Ecology, and Conservation

When, in the mid 1990s, technological advances permitted us to build radio transmitters capable of sending signals to satellites orbiting the earth and small enough to place on an Osprey, windows into their lives away from the nest were thrown wide open. Thanks to bird band recoveries, we already knew that most North American Ospreys migrate to South America, and we had a reasonable feel for the routes and timing of their migrations. But because almost all band returns are from dead birds, we lacked the fine details of their migratory routes and knew little of their movements around the nest during the breeding season. How far from home do they go to catch fish? When they migrate, do they follow the same path each year? Do they winter in the same locations? Where in the migratory cycle does most mortality occur? Are there bottlenecks where conservation intervention might help the species? How do young birds find their way to South America? Is the timing and relative importance of different sources of mortality the same for adults as it is for juveniles on their first migration south?

Rob Bierregaard has been tagging Ospreys in the eastern U.S. since 2000. He has deployed satellite transmitters on 61 juvenile and 47 adult Ospreys. His studies—the first to collect a significant body of data on juvenile migration—have led to surprising discoveries about the dispersal and migration of naïve Ospreys as they leave their natal territories and explore the world around them. Ever-more sophisticated satellite transmitters have enabled us to document in unprecedented detail the hunting behavior of adult males feeding their families and the fine details of their behavior on migration.


Research Associate
Academy of Natural Sciences
Drexel University, Philadelphia, PA

Dr. Richard (Rob) Bierregaard co-authored the Osprey account for the Birds of North America Project, wrote the 81 species accounts for the Neotropical Falconiformes in the Handbook of Birds of the World, and edited Tropical Forest Remnants: Ecology, Management and Conservation of Fragmented Communities, as well as Lessons From Amazonia: The Ecology and Management of a Fragmented Forest.

He is a Fellow of the American Ornithologists Union and the Delaware Valley Ornithological Club and was recently elected to the Board of Directors of Pennsylvania Audubon and re-elected to the Board of Directors of the Raptor Research Foundation.

From 1995 to 2011, Dr. Bierregaard taught Ornithology and Ecology in the Biology Department of UNC-Charlotte. In 2011 he moved from Charlotte to Wynnewood, PA, where he is now a research associate of the Academy of Natural Sciences of Drexel University.

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