Woodland Park Zoo Wildlife Conservation

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Washington State

Raptor Ecology
of the Shrub-Steppe
The population of Washington state's threatened ferruginous hawk has declined in recent times, due to loss and degradation of nesting habitat, as well as persecution and reduction of important prey such as ground squirrels and jackrabbits. Because the hawks are migratory, the entire picture of their decline could not be understood without knowledge of their migration and wintering areas. The birds leave Washington each year in early summer, and typically return before the next spring. The story of their travels was unknown before this study began.

Visit the Ferruginous Hawk Field Study page to view interactive maps and latitude/longitude tables tracking the migratory movements of these fascinating birds of prey.

Tri-National Satellite Telemetry Project
Find out about the current Tri-National satellite telemetry project that tracks ferruginous hawk migration. This work resulted partially from the Washington State study that Woodland Park Zoo collaborated on. Hawks are tracked from U.S. and Canadian locations, as well as back to breeding territories from wintering grounds in Mexico.

PARTNERS:

Washington Department of Fish & Wildlife
Woodland Park Zoo
Bonneville Power Administration
US Department of Energy
Battelle Pacific Northwest National Laboratories
Thermosight Inc.

LINKS:

Ferruginous Hawk
Click here to view the Hawk Cam
The Hawk Cam is now live for 2008!

Collaborative Effort
Woodland Park Zoo (WPZ) and the Washington Department of Fish and Wildlife (WDFW) have collaborated on a project tracking ferruginous hawks since 1999. WPZ raptor keepers including Tom Aversa, Becky Barker, Gretchen Albrecht and Sara Manetti have worked as field assistants. Trapping of adults was only conducted when well-developed fledglings were in the nest to insure that the nest was not abandoned. The scientists used a great-horned owl from the WPZ Raptor Center, as a lure, to capture the adults. The owl represents a threat to the safety of the juvenile hawks, and consequently their parents attempt to drive the intruder away. In a frenzy of protective parental instinct, the hawk becomes entangled in the triangle of nets that surround the tethered owl. Juvenile hawks were also trapped at their nests so that adult and juvenile migration patterns could be studied and compared. Each hawk was weighed, measured and fitted with a satellite radio transmitter. Because of the great range over which the hawks migrate, it is necessary to use special transmitters that transmit directly to satellites from wherever the bird is located. These units are very expensive, costing around $3,000 each.

Tracking the Hawks
Once fitted with the transmitters, scientists begin to gather valuable information on the hawk’s migratory patterns. Satellite tracking has proven extremely successful. Transmitters were deployed on 26 hawks from southeastern Washington from 1999-2002 and most returned valuable migration information. Most of the birds initially traveled east to the Montana/Alberta area, feasting on an abundance of ground squirrels there. When squirrels went underground for the winter, the hawks moved on, with some birds heading south to the plains states and their prairie dog colonies, and many others crossing back over the continental divide to winter in California's central valley. It had previously been thought that two discrete populations of hawks existed, one on each side of the divide. However, actual movements showed that the divide was not a physical barrier to hawk migration. Information on migration routes has indicated that out-of-state illegal shooting and proximity to agricultural pesticides could impact Washington’s hawks. Population numbers and productivity have also been studied through nest surveys, primarily in 2002 and 2003. Information gained from this project allows scientists to create a management plan encompassing problems encountered by hawks throughout their entire migration.

Habitat in Danger
The shrub-steppe ecosystem the ferruginous hawks inhabit is also threatened, decreasing in both quality and quantity at alarming rates. Shrub-steppe decline is similar to old-growth forest loss, although its demise has been less publicized. Many people regard this ecosystem as a wasteland, and do not recognize its stark beauty or the unique species that are found there and nowhere else. A goal of the hawk project has been to aid in the protection of shrub steppe and prairie habitats. Project coordinators hope to spark interest in habitat conservation by disseminating project results via the WPZ and WDFW websites, as well as through zoo outreach and on-site programs and publications. This cooperative WDFW/WPZ project, has been funded by grants from The Boeing Company, the Burning and Weissman Foundations, the International Association of Avian Trainers and Educators and WPZ's Conservation Education and Jungle Party Conservation funds. WPZ participates directly in the study by assisting with trapping, monitoring and undertaking nest surveys.