Scientists say an outbreak of avian salmonella is killing songbirds in Marin and likely spreading via outdoor bird feeders.
"We have received several calls about dead birds around the feeders," said Melissa Pitkin, education and outreach director for PRBO Conservation Science, a wildlife organization. "Bird disease can occur at feeders and because different birds use them over and over, a disease can spread fast."
Calls have come from the Point Reyes and Inverness area in West Marin, but also from more urbanized areas on the east side of the county, officials said. Pine siskins and goldfinches are being affected the most.
People who have put out bird feeders are being asked to wash them with soap and water, then disinfect with 10 parts water per one part bleach. The feeders should then be left down for three weeks so sick birds do not re-infect the feeder.
"We are definitely seeing more cases this winter," said Veronica Bowers, songbird specialist with WildCare in San Rafael.
Salmonellosis is caused by a bacteria belonging to the genus salmonella. It is a common cause of mortality in feeder birds, but the symptoms are not always obvious. Sick birds may appear thin, fluffed up, and may have swollen eyelids. The disease cannot be spread to humans.
They are often lethargic and easy to approach. Some infected birds may show no outward symptoms but are carriers of the disease and can spread the infection to other birds, Pitkin said.
Salmonellosis is primarily transmitted by fecal contamination of food and water by sick birds, though it can also be transmitted by bird-to-bird contact. Occasionally, outbreaks of the disease cause significant mortality in certain species, Pitkin said.
WildCare has a hotline to report potentially sick songbirds: 456-7283.
Read more West Marin stories at the IJ's West Marin section.
Contact Mark Prado via e-mail at email@example.com