Portland Audubon’s 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.
In fall 2012, our staff and volunteers 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. Their work provides a good case study for the care center’s crisis response capabilities.
Avian Botulism at Smith and Bybee
The 2012 Smith and Bybee outbreak began in early September, and the timing couldn’t have been worse for the thousands of migrating waterfowl who arrive at the wetlands each fall. More than 3,000 birds died as part of the outbreak.
Metro, the regional government and owner of Smith and Bybee, coordinated the response to the outbreak and collected deceased birds, while birds found alive were transported to Audubon. Our goal was to treat the birds and release them back into the wild, since they do not suffer any long-term damage from botulism.
A big thank-you goes out to the following staff and volunteers from the Oregon Department of Fish and Wildlife and Metro — they each put in a number of hours recovering and triaging birds. ODFW staff: Dr. Julia Burco, Julia Back, Shona Wilson and Don Vandenberg. ODFW volunteers: Nate LaHue and Scott Kinney. Metro staff: Katy Weil, Jacob Baynes and Chapin Pier. Metro volunteer: Kelly Walker.
Bacteria were at the root of the botulism outbreak, but they weren’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 worked hard to contain the outbreak, the end was only in sight when cool, rainy weather returned to Portland. Cold temperatures suppressed the bacteria and rain flushed out the lake.
Response and Treatment
To care for the influx of birds from Smith Lake, the care center hired an additional staff person and asked volunteers to take on more shifts — and our volunteers really stepped up to the plate. Every day, we had three extra volunteers who devoted all of their time to the Smith birds, and several others shuttled birds from the lake to the care center.
When the birds arrived at Audubon, most had paralysis and were unable to stand, and some also had eye issues. Each received an initial exam and a dose of fluids.
Staff and volunteers then provided supportive care while the botulism worked its way out of the birds’ systems, a process that takes about a week. Supportive care included tube-feeding the birds three times a day and keeping them warm with heating pads and heat lamps.
Once a bird had recovered, it was federally banded and then released 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 admitted a total of 182 birds for botulism treatment; 112 of them were released and 70 died or were euthanized.
Of the deceased birds, two were dead on arrival and 30 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 – nearly 80 percent pulled through, which is a remarkable recovery rate. Care center staff and volunteers are particularly proud of how well American Coots did.
“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 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