Tundra Swan Rescued After Mass Waterfowl Casualty Event
News Release – November 15, 2022
A tundra swan in the care of Think Wild was lucky to survive a casualty event that killed many other migrating waterfowl near Burns last week. Biologists think a lunar eclipse and snow storm may have affected the birds’ ability to navigate successfully.
Last Wednesday, Nov. 9, Lee Foster, a district biologist with Oregon Department of Fish and Wildlife (ODFW) in Burns, reached out to Think Wild, Central Oregon’s wildlife rehabilitation hospital, about an injured Tundra Swan. This swan was found in the town of Drewsey, Oregon, among as many as thirty swans, geese, and other waterfowl that died during their fall migration. Area biologists are unsure what caused this mass casualty event, but Foster hypothesized that a combination of the lunar eclipse and a snow storm may have disoriented the migrating birds, causing them to fly into power lines, light posts, or the ground.
While most of the found birds suffered fatal or non-repairable injuries, the surviving swan was nonflighted but did not have any obvious injuries. ODFW contacted Think Wild to arrange for medical care, and the next morning, Think Wild Rescue and Transport Volunteer, Karla Harris, transported the swan to the wildlife hospital.
Think Wild Veterinarian, Dr. Laura Acevedo, performed an exam and took radiographs of the Tundra Swan outdoors in the waterfowl enclosure, wearing masks, gloves, and surgical gowns to ensure biosecurity, as swans and other waterfowl can be carriers of the Highly Pathogenic Avian Influenza (HPAI). “We found no significant fractures or injuries, but the swan does have bruising and likely soft tissue damage that will need time to heal,” said Dr. Acevedo. “Think Wild will provide ample space, food, medications for pain management, and time for recovery.”
Due to concerns about the Highly Pathogenic Avian Influenza (HPAI), Think Wild maintains strict biosecurity protocols in the wildlife hospital and is quarantining the Tundra Swan from other avian patients. The swan has shown no symptoms of the virus. Because the casualties and injuries during the event were clearly caused by collisions with power lines and the ground, district biologists are fairly confident that HPAI is not a factor. Wildlife rehabilitators in the state are still prohibited from accepting waterfowl patients except in rare cases such as this casualty event.
Tundra Swans are large waterfowl native to North America. They spend their summers breeding and feeding in the arctic tundra in northern Alaska and Canada, and migrate south to coastal estuaries, wetlands, and large lakes for the winter. Tundra Swans are most common in Central Oregon during fall and spring migrations, and can be spotted throughout the Willamette Valley and south into California’s Central Valley during the winter.
Migration routes can be long and dangerous for birds. Tundra Swans migrate long distances, sometimes traveling day and night for as much as 1,000 miles at a time. Climate trends toward larger, wetter storm systems on the West Coast during fall migration, as well as drought and habitat degradation, may affect tundra swans’ population success over time. This year’s quick transition from unseasonably warm fall temperatures to freezing snow storms may have contributed to this migration casualty event in Harney County last week.