Salmonella killing songbirds in California as experts urge removal of bird feeders to stem disease
A bacterial disease spread largely at bird feeders meant to help our feathered friends is killing songbirds by the thousands around Sonoma County and across other parts of the state, according to the California Department of Fish and Wildlife.
The tiny pine siskin, a type of finch which breeds largely in Canada’s boreal forests and winters in California and other areas of the United States, represents the majority of sickened birds, though several other finch species also have been affected.
Bird experts say the best way to help them is to take down bird feeders and bird baths, eliminating the places they congregate and imposing a kind of social distancing on those species vulnerable to infection.
“It’s just reached a point where it’s more effective to just completely remove the feeders and bird baths and just let the birds move through the area, and then in spring, when the pine siskin is no longer in the area, you can put them back up,” said Ashton Klutz, executive director of the Bird Rescue Center of Sonoma County.
It’s a hard thing to ask of bird lovers right now, given how much time people are spending at home and how delightfully distracting an active bird feeder can be, said Veronica Bowers, director and founder of Native Songbird Care & Conservation in Sebastopol.
But it’s also what’s needed to prevent further spread of salmonella, said Bowers, who like other bird rescue centers in the area has been inundated with reports of sick, dying or dead birds.
“We’ve had many tearful, difficult discussions with our community members over the past month about asking them to remove bird feeders,” Bowers said. “Some people have been really good during the shutdown, and often their bird feeders are their only connection to the natural world, and to ask them to take down their bird feeders is hard, but necessary.”
A highly streaked brown and white bird with a very pointy beak and flashes of yellow on its wings and tail, the pine siskin has a widely varying range, potentially dictated by food availability, said Krysta Rogers, an senior environmental scientist and avian disease specialist with state Fish and Wildlife.
Last year was an apparent boom year in Canada, with abundant population growth as a consequence, leading to more birds than could be supported by this year’s more meager seed crop. What’s called an “irruption” of pine siskins resulted — a mass migration of the species to all corners of the continent, eagerly availing themselves of both naturally available foods and those set out for them by people.
But where they normally would find a source of food, deplete it and move on, the ever-present supply at bird feeders means they hang around, instead. That, in turn, makes the transmission of salmonella, a gut bacteria, more likely, as birds stepping in feces from an infected bird or eating seeds mixed with waste on the ground contaminate their food or water, perches and other surfaces, ingest the bacteria and become infected.
Salmonellosis kills most birds within about 24 hours of infection, causing inflammation in the throat and deterioration of the intestinal tissue. “They’re kind of dying from the inside out,” Bowers said. “The bacterium is very cruel.”
Though some have been brought to rescue organizations for treatment, there is little that can be done.
Sickened birds will quickly become emaciated, but likely will appear puffed up and still, with their eyes partially closed.
“They’re going to be fluffed up,” said Alison Hermance, communications manager at WildCare in San Rafael. “They’re going to be to be lethargic. They’re going to be the last bird to fly away if the flock is startled.”
They’re also going to be more vulnerable to being preyed upon by cats or other animals, which also are at risk of infection if they ingest a contaminated bird, experts said.
Anyone who handles a dead bird should use gloves and wash carefully to avoid infection or transmission.
A similar outbreak occurred in December 2015 through March 2016, Rogers said.
North Bay bird rescue organizations received their first reports in the latest occurrent in late November, building through December and mostly peaking in January, when Hermance said WildCare was “getting dozens of birds a day into the hospital.”
Rogers said she’s received reports of more than 200 incidents in the North Bay, though each report might represent more than one bird. Many more birds likely died unseen and unreported, with outbreaks reported around the greater Bay Area, the Central Coast and the Sierra Nevada foothills, at least.
Another spike also is likely with the spring migration back north to breeding grounds, unless people take down bird feeders before then, Rogers said.
Klutz said people desperate to bring birds to their yards can still put up humming bird feeders but remember they, too, require regular cleaning, a good habit for anyone who owns a bird feeder or bath.
And once the pine siskins leave the area, their other bird feeders can go back up, as well.
She said it’s difficult for people to recognize that something they’ve been doing to try to help the birds may have hurt.
But “the response we’ve gotten from the community has definitely been one of understanding that, even in this negative situation, has been a great positive,” Klutz said. “Even though we’ll miss having our bird feeder up, just to remember it’s only temporary, while we’re doing the best we can now that we know what’s going on, for the betterment of the birds.’
You can reach Staff Writer Mary Callahan at 707-521-5249 or firstname.lastname@example.org. On Twitter @MaryCallahanB.