Salmonella in wild birds
(Early 2021): there is an ongoing outbreak of salmonellosis in the wild bird population on the West Coast of the United States. Reports of dead and dying songbirds are widespread. Songbirds are frequently affected by this disease this time of year, resulting in large-scale deaths [1]. Read below for more information and for what you can do to help.
About Salmonella
Salmonella bacteria can infect many types of animals, including birds, cattle, rodents, reptiles, amphibians, and humans. The most common species of Salmonella is Salmonella enterica. Infection is called salmonellosis and often is asymptomatic, but for the wrong species or under the wrong circumstances, an infection may result in diarrhea, serious illness, or death.
Some species are more frequently affected than others, as shown in the diagram below.
"Relative occurrence of species found dead from salmonellosis outbreaks at bird feeding stations within the United States." [1]
Bird Feeders Exacerbate the Problem
Bird feeders exacerbate the disease's spread during an outbreak [1][3], as they provide a location for birds to gather, potentially spreading the disease through their droppings and saliva.
Bird feeders can also spread other pathogens, so it's essential to keep them clean even outside of a Salmonella outbreak. For example, avian pox, trichomoniasis, parasites, mites, etc.
Recognize Sick Birds
Sick birds can be easy to spot. Birds often exhibit these symptoms:
- Ruffled feathers
- Lethargic
- Tame when approached
Actions You Should Take
During a Salmonella outbreak
During an outbreak, or if you see sick or dead birds at your feeders, we recommend:
- Discontinue use of bird feeders and baths for at least two weeks.
- Hummingbird feeders can usually continue to be used.
- Wash feeders and baths thoroughly before returning them to service.
Your local authorities may advise stricter controls, and you should always follow those when issued.
Salmonella doesn't go away quickly. According to the FDA, "The bacteria can survive several weeks in dry environments and several months in wet environments." [2], and some sources say it can live for 28 months in bird poop [1].
During an outbreak, surfaces should be manually cleaned at frequent intervals. Since it is difficult to comply with this protocol, we recommend taking the targeted feeders down entirely until it is safe.
Normal Feeding Tips and Protocols
These are the normal protocols you should follow to keep sanitary conditions for the wild birds, which will reduce the likelihood of outbreaks:
Feeder selection
- Choose a design that prevents birds from pooping in the food. Tubes are better than platforms [5].
- Avoid seed catchment trays, they may catch poop in addition to seeds, and then birds may later eat from the tray.
- Pick a design that is easy to disassemble and scrub down.
- For salmonella in the kitchen, the FDA encourages use of both wood and plastic cutting boards. Because of this, we think either material is OK for feeders.
- Place feeders to prevent birds from perching above and defecating onto a feeder below.
- Thoroughly disinfect feeders twice a month.
- Remove spilled food and seed casings regularly.
- Empty and clean birdbaths weekly [4].
- Always wash your hands after touching feeders and after touching potentially contaminated surfaces.
[1]Pages 99-110 in Field Manual of Wildlife Diseases: General Field Procedures and Diseases of Birds by Ciganovich et al.
[2] FDA: Get the Facts about Salmonella
[3] Cornell Salmonella Fact Sheet