Studying the evolution of virulence in bird disease, researchers discovered that virulence increases once a disease is established in an area. They suggest that evolution toward virulence is assisted by easy transmission around bird feeders.
Bird watchers can do their part to help House Finches and other backyard birds by washing their feeders in a 10 percent bleach solution twice a month.
A novel disease in songbirds has rapidly evolved to become more harmful to its host on at least two separate occasions in just two decades, according to a new study. The research provides a real-life model to help understand how diseases that threaten humans can be expected to change in virulence as they emerge.
... when it gets established in a new location, there are lots of other potential hosts, especially around bird feeders. It can evolve toward being a nastier illness because it’s getting transmitted more quickly."
Good article Ruth!
I am totally supportive of cleaning bird/hummingbird feeders, and do it, but refuse to use bleach.