Salmonellosis is a severe disease caused by Salmonella bacteria. It can affect all species of wild birds, as well as humans and pets.

The effect that Salmonellosis will have on a bird depends on its general health. The most noticeable symptom of Salmonellosis is lethargy. Infected birds are usually described as "tame" and fluffed up. Death follows quickly in severe cases, especially if the bird was already in poor condition or environmentally stressed (during very cold or hot weather).

Birds are infected with Salmonella bacteria when they eat food or drink water contaminated with feces from other birds that carry the bacteria in their intestines. Birds are most at risk when they are at group bird feeders or water sources. When many birds eat or drink in one place, there is a higher risk that feces from infected birds will end up on seed, feeders, or in water.  Domestic cats that capture and eat infected birds, and humans who have handled infected cats or birds, are also at risk of developing Salmonellosis.