Here in North Central Florida, we have mostly escaped the effects of a possible winter Salmonellosis outbreak in Pine Siskins and a few other species of overwintering birds but it is here and you should know how to handle sanitization at your feeders in order to minimize the risk to any of your feeder birds.

Salmonellosis is a type of food poisoning associated with the bacterium 'Salmonella enterica.' "In birds, clinical signs include ruffled feathers, diarrhea, and lethargy." (See link to Cornell Wildlife Health Lab - Salmonella - at the end of this post). It is transmitted through fecal-oral contact - in other words, when birds get fecal material on their skin or feathers that is eventually ingested through foraging and/or preening.

Birdfeeders are most commonly associated with salmonellosis outbreaks during winter when large flocks of overwintering species such as Pine Siskin or Brown-headed Cowbird compress into relatively small areas like clusters of birdfeeders and share surface area with many other birds (and perhaps squirrels).

You should take great care to maintain clean feeders at all times but if you see evidence that your feeder birds are defecating on feeders, feeder accessories, hanging hardware, the ground around the feeders, etc. you should do the following immediately: use a mixture of 10% bleach and scrub every bit of surface area on all of your feeders, feeder accessories, and hanging hardware. Allow the bleach to "work" for about 10 minutes. Rinse the bleach reside thoroughly. Place fresh seed in the feeders and continue with vigilance. Discontinue broadcast (bare ground) feeding immediately and clean/rake the vegetation and soil in any areas that birds have gathered on the ground. The species most commonly affected by salmonellosis also seem to be among the most likely to feed on the ground around feeders.

If you observe any bird exhibiting signs of salmonellosis then you should clean as above and consider taking feeders and baths down until the affected birds have moved on. Here in North Central Florida, we have not experienced the great densities of Pine Siskin that have occurred this winter in much of the rest of the continent nor has salmonellosis become widespread in any other species.

However, we are receiving reports of isolated cases in individual feeder birds about once per week with Brown-headed Cowbird being the most commonly reported species. In such cases, you may be hosting a bird that has become infected by association with other birds at a roosting spot and poses only a slight risk at your feeders/baths. If so, you may safely continue feeding birds as long as you sanitize adequately and remain vigilant for signs of spread to other birds and the presence of feces at feeders, baths, and on the ground around feeders and baths.

This final point is not being discussed elsewhere as far as I can tell but I firmly believe that excluding squirrels from feeders can significantly reduce the risk of transmitting feces from the ground to the feeder. Although finches (i.e. American Goldfinch, Pine Siskin) are notoriously messy at feeders when aggregating there in winter months, most birds cast feces away from feeders. If you feeders are arranged in such a way that feces will not land on a feeder below then that feces is less likely to be a vector for transmission. However, if squirrels are foraging in the wasted food material on the ground below a busy feeder array then they are also encountering feces and to a much greater degree than a bird since so much more surface area is in contact with that feces. If squirrels can climb hardware, especially if they are able to all the way to feeders, then the rate of transmission could be far higher at such a feeder.

(https://cwhl.vet.cornell.edu/disease/salmonella?__hstc=196419891.49372bcac4805b64e1c3e8c2722b2184.1616339849623.1616339849623.1616339849623.1&__hssc=196419891.1.1616339849623&__hsfp=3268614734)