Lead-testing machine funded by Oregon Zoo helped save poisoned raptor, vets say
After more than three months of intense treatment, a bald eagle in the care of the Audubon Society of Portland has made a full recovery from severe lead poisoning. The raptor will be released back into the wild at Willow Grove Park near Longview, Wash., at 11 a.m. on Aug. 24. The public is welcome to attend the release.
"The eagle is in excellent health and has met all of the standards we set for birds going back into the wild," said Portland Audubon veterinarian Deb Sheaffer. "Its lead levels have dropped and it has been flying beautifully in a flight cage we use to get raptors ready for release."
"Reducing wild animals' exposure to lead in Oregon is one of our long-term goals."
—Bob Sallinger, Portland Audubon conservation manager
Found in May near Longview, Wash., the adult eagle likely became poisoned after eating the remains of an animal shot with lead ammunition, ingesting fragments of ammunition along with the carcass. Veterinarians credit a state-of-the-art lead-testing machine provided by the Oregon Zoo for quickly diagnosing and treating the poisoned raptor. In addition to having high levels of lead in its blood, an X-ray revealed metal in the bird's stomach.
"It's always exciting to release rehabilitated wildlife, but particularly so in this case," said Sheaffer. "The eagle was just so sick when it arrived at our door, and staff and volunteers have put many hundreds of hours into caring for the bird – it's very rewarding to see it head back into the wild."
During its time at Portland Audubon's Wildlife Care Center, the eagle not only received treatment for lead poisoning, but also contributed to research that may help protect other wildlife from lead.
In January, with an assist from the Oregon Zoo, Audubon launched a study of lead's impact on local birds like this eagle. For every raptor the care center admits, staff members draw a blood sample, running it through a state-of-the-art machine that tests for lead, and recording the results in a growing database to track the extent of exposure in local raptor populations.
"Reducing wild animals' exposure to lead in Oregon is one of our long-term goals," said Bob Sallinger, Portland Audubon conservation manager. "Getting a handle on how many local birds are being affected and killed by the toxin is an important first step."
The research is made possible by a grant from the zoo's Future for Wildlife program, which funded Audubon's purchase of the Lead Care II machine — a small countertop device that in less than three minutes can determine the amount of lead in a drop of blood.
Lead poisoning, despite the damage it wreaks on birds' nervous and digestive systems, is tricky to diagnose without a blood test. Poisoned raptors may have easy-to-identify symptoms like paralysis and seizures, but some exhibit inconclusive symptoms like lethargy. Others die without showing any symptoms at all.
"Because lead poisoning is so hard to diagnose from symptoms alone, the lead-testing machine is helping us catch and treat more cases," said Sheaffer. "The machine's quick results certainly made a difference for this bald eagle – its lead levels were so high that any delay in treatment could have been fatal."
In addition to raptors, Audubon's care center is testing all ravens and vultures that come through the door. Taken together, these are the Portland-area birds most likely to eat the remains of animals shot with lead ammunition.
Since January, the care center has collected lead levels from 15 species. The first round of results will be analyzed and published at the end of this year; more than 200 raptors, vultures and ravens pass through the care center in an average year, a good sample size for the study.
photos courtesy Audubon Society of Portland