Northern harriers, long-winged rodent-hunting hawks, make impressive migrant journeys. Research by UC Davis’ Hull Lab sheds new light on these journeys. Harriers are a familiar sight in California’s wetlands, especially in winter. Researchers captured fifteen female harriers–ten in winter, five in spring–in Suisun Marsh and equipped with 14-gram GPS backpack transmitters, too heavy for use with the smaller males. Telemetry data from seven of the ten winter females revealed migrations of up to 600 miles, to nesting sites from the San Joaquin Valley to Washington State and Idaho. The eighth, nicknamed Blanca for her pale yellow eyes, flew through British Columbia and Alaska all the way to the Arctic tundra, a 7,000-mile round trip that set a distance record for her species. She and her fellow travelers used wildlife refuge wetlands as stopovers. The five spring-caught females stayed closer to Suisun. Lead researcher Joshua Hull plans to use newly available 10-gram transmitters to track male harriers. The project will help wildlife managers better understand the habitat needs of this raptor, a California Species of Special Concern whose numbers in Suisun Marsh and elsewhere have declined.
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Plus Three Great Migration Stories by Joe Eaton.