Botulism outbreak at Smith and Bybee
Oct. 22, 2012: The Wildlife Care Center is often on the front lines when local wildlife populations experience a crisis, providing a variety of services that help contain emergencies and rehabilitate ill or injured animals. This fall, our care center staff and volunteers have swung into action as part of a city-wide response to an avian botulism outbreak at Smith Lake, located in the Smith and Bybee Wetlands Natural Area.
A care center volunteer holds a Northern Shoveler, one of several of this species that Portland Audubon treated for botulism - Tinsley Hunsdorfer
The Wildlife Care Center is often on the front lines when local wildlife populations experience a crisis, providing a variety of services that help contain emergencies and rehabilitate ill or injured animals.
This fall, our care center staff and volunteers have swung into action as part of a city-wide response to an avian botulism outbreak at Smith Lake, located in the Smith and Bybee Wetlands Natural Area.
The care center has taken in more than 150 birds with botulism; at the height of the outbreak, we hired an additional staff person and brought on an extra three volunteers each day to care for the Smith Lake birds.
Avian Botulism at Smith and Bybee
The ongoing Smith and Bybee outbreak began in early September, and the timing couldn't be worse for the thousands of migrating waterfowl who arrive at the wetlands each fall. Wildlife officials estimate that more than 2,000 birds have died so far.
Metro, the regional government and owner of Smith and Bybee, has been coordinating the response to the outbreak and collecting deceased birds, while birds found alive are transported to Portland Audubon. Our goal is to treat and release the birds back into the wild, since they do not suffer any long-term damage from botulism.
A big thank-you goes out to Oregon Department of Fish and Wildlife staff and volunteers, who are putting in a number of hours recovering and triaging birds. Specifically, staff members Dr. Julia Burco, Julia Back, Shona Wilson and Don Vandenberg, and volunteers Nate LaHue and Scott Kinney.
Bacteria are at the root of the botulism outbreak, but they aren't the direct cause of bird death. Active botulism bacteria produce a paralyzing toxin, and waterbirds that ingest the toxin often drown because they cannot lift their necks. Avian botulism is typically spread when birds eat maggots carrying the toxin.
To become active, botulism bacteria need warm temperatures, organic matter and an oxygen-free (anaerobic) environment. While Metro is working hard to contain the outbreak, the end will only be in sight when cool, rainy weather returns to Portland. Cold temperatures will suppress the bacteria and rain will flush out the lake.
Avian botulism poses a very low public health risk, but the Smith and Bybee Natural Area will be closed to paddlers until the outbreak ends. Visit the Metro website for more information.
Response and Treatment
To care for the influx of birds from Smith Lake, the care center has hired an additional staff person and asked volunteers to take on more shifts — and our volunteers have really stepped up to the plate. Every day, we now have three extra volunteers who devote all of their time to the Smith birds, and several others have been shuttling birds from the lake to the care center.
When the birds arrive, most have paralysis and are unable to stand, and some also have eye issues. Each receives an initial exam and a dose of fluids.
Staff and volunteers then provide supportive care while the botulism works its way out of the birds' systems, a process that takes about a week. Supportive care includes tube-feeding the birds three times a day and keeping them warm with heating pads and heat lamps.
Once a bird has recovered, it is federally banded and then we release it back into the wild on Sauvie Island. Wildlife biologists want to know if the birds we’ve treated try to return to Smith and Bybee, and bands are the easiest way to identify them.
Intakes and Releases
The care center has admitted a total of 158 birds for botulism treatment since the outbreak began. As of Oct. 20, 88 of them have been released, 14 are still in our care, and 56 have died or been euthanized.
Of the deceased birds, two were dead on arrival and 27 died within their first full day at the care center, which means they were too far gone for us to help them.
Of the remaining birds – those that stood any chance of recovery – about 80 percent have pulled through, which is a remarkable recovery rate. Care center staff and volunteers are particularly proud of how well American Coots have been doing.
“We’ve been able to release almost all of the American Coots that came in, and according to the U.S. Geological Survey field manual of wildlife diseases, these birds are notorious for being difficult to rehab and some wonder if it’s worth it to even try,” said care center manager Lacy Campbell. “I guess it was for us!”
The care center has admitted the following species for botulism treatment:
- Northern Pintail
- American Widgeon
- Green-winged Teal
- American Coot
- Great Blue Heron
- Wood Duck
- Long-billed Dowitcher
- Northern Shoveler
- Hooded Merganser
- Lesser Yellowlegs