For the Birds: Salmonella and irrupting finches

Across the country, small, striped brown birds with flashy hints of yellow are swarming bird feeders. These delightful birds are pine siskins. Since October of 2020, the tiny finches have streamed south by the thousands in a record-breaking migration event. In one sighting, birders counted a cloud of over 5,000 in October in Cape May, New Jersey.

The pine siskins are not alone; evening grosbeaks, common redpoll, Cassin’s finch, red crossbill, and even red-breasted nuthatch have abandoned the north because the cone crop is lacking. Mass movements like these, called “irruptions,” explain why one year you might find just a few of a species at the feeder, and the next a barrage. These finches target the seeds, cones, and buds of the mountain and boreal forests that cross Alaska and Canada. They’re currently amassing in forests throughout the country and on urban cone-bearing trees and bird feeders, even making surprise appearances in the Gulf states and Bermuda.

Unfortunately, some are falling ill with bacterial infections from a potent salmonella strain, S. Typhimurium. Originally from agricultural poultry farms, salmonella is now a world traveler, affecting birds as remote as Antarctic penguins. The finch family of birds is all particularly vulnerable to this intestinal squatter. Pine siskins are getting hit hard with it.

Salmonella is a survivalist; it can last weeks to months in the environment, enduring freezing and hot temperatures. The longer a pathogen lives, the more it accumulates. Anywhere fecal matter can contaminate food or water is a danger zone; sadly, that is some of our most popular feeders. A bird sitting in a tray of food can be spreading disease.

Michelle Dennehy of the Oregon Department of Fish and Wildlife (ODFW) explains that, “Salmonella, e. coli, and other bacteria along with viruses, parasites, and fungal diseases can be passed at feeders that don’t get cleaned regularly.” Stress is also a launching pad for disease. Pine siskins swarmed south due to a lack of food. That hunger, along with cold weather, creates a lot of stress.

In pine siskins, salmonella is often lethal. The bacteria affect the intestinal tract, preventing food digestion, and then invade the organs and brain. Ill birds appear tired and lethargic, sitting for long periods at the feeder or perhaps acting tame when approached. You may find them deceased.

The good news is that we can fight disease at the feeder by being good stewards.

“When you feed birds, be sure to start with clean feeders and to disinfect feeders,” says Dr. Colin Gillin, ODFW State Wildlife Veterinarian. Here are a few key tips:

• If birds are dying at your feeder, remove the finch feeders for a couple of weeks.

• Remove any feeder that lets a bird get their rear over the food.

• Wash feeders once a week if you have large numbers and/or sick birds.

• Thoroughly disinfect feeders: take apart, scrub, wash, soak in 10 percent bleach bath, wash with soap and water, rinse, dry thoroughly.

• Wash birdbaths. Use bleach if you can without getting it in the environment.

• Feed individual seeds in feeders, so seeds are not tossed to the ground.

• Avoid wood, flat, or seed-catching type feeders.

• Mesh and hoppers work great (Sisters Feed Store has a nice hopper and is stocked up on seed).

• Clean and remove debris from under the feeder.

• Spread the feeders out rather than congregating them.

For more information go to www.nativebirdcare.org/blog. You can call ODFW at 866-968-2600 or email [email protected]

Text Native Bird Care at 541-728-8208 if you see sick birds.