Since mid-December, a fatal disease outbreak has killed increased numbers of pine siskins, a small songbird that inhabits California's forested areas.
Scientists from the California Department of Fish and Wildlife (CDFW) believe that infected bird feeders and bird baths are partly responsible for the spread.
These outbreaks have primarily been reported along the central and south coasts as well as near Redding.
CDFW has received 138 reports since early December representing a minimum of 300 known dead birds. Scientists estimate the actual number to be more than 1,000 birds.
CDFW's Wildlife Investigations Laboratory has evaluated carcasses from several locations and determined the cause of mortality to be Salmonellosis, a disease caused by Salmonella bacteria.
Birds become infected with Salmonella bacteria when they ingest food or water, or come into contact with objects, including bird feeders, perches and soil, contaminated with feces from infected birds.
Sick birds often appear weak, have labored breathing, and may sit for prolonged periods of time with fluffed or ruffled feathers. Salmonellosis is highly fatal in pine siskins, with most birds dying within 24 hours after infection.
"There are two important things that the public can do to help prevent bird deaths," explained CDFW Senior Environmental Scientist Krysta Rogers, an avian disease specialist. "First, they can remove all artificial sources of food and water such as bird feeders, bird baths and fountains. Secondly, they can report bird deaths to CDFW, particularly when large numbers of birds are found in an area. This information helps us to better monitor disease outbreaks so that we can take appropriate action."
Dead birds may be reported to CDFW's Wildlife Investigations Lab to help determine the locations and numbers of birds affected during this Salmonellosis outbreak. Mortality can be reported via this link: www.wildlife.ca.gov/conservation/laboratories/wildlifeInvestigations/monitoring/mortality-report .
Outbreaks of Salmonellosis in pine siskins appear periodically in some years, with the most recent outbreak occurring in winter 2015.
"The majority of the Salmonellosis reports we receive are from locations with backyard bird feeders," said Rogers. "These devices may aid in disease transmission between pine siskins, and possibly other bird species, by bringing the birds into closer contact than would occur normally."
If sick birds are observed, please contact a local wildlife rehabilitation center for advice.
A list of CDFW-licensed centers can be viewed at www.dfg.ca.gov/wildlife/wil/rehab/facilities.html .
