Learned Something New - House Finch Conjunctivitis

Putative Mycoplasmal conjunctivitis

Each of the past three years, we have noticed male House Finches with crusty, watery eyes. Along with this, last year and the year before, other finches seemed to be aggressive towards the invalid - pecking at the eyes. We only saw one bird in each of the years, and only with males. The disheveled bird shown in this photograph  was hanging around our yard - able to fly to and from the seed feeder and having a good appetite - but over a three day period seemed to be getting weaker. The last time I saw him, was last Wednesday morning when he was walking on the patio, seeming weak and having difficulty walking without tripping - I haven't seen him since. Until today, I assumed the pathology was inflicted by other birds pecking at the victim, but when Google'ing about House Finch aggressive behavior, I came on a blog from a few years ago that mentioned conjunctivitis. When I referenced "House Finch Conjunctivitis" in another search, the link at the top of the result list was from the Cornell Lab of Ornithology. There is a good description about the disease at the site, and it is good to know what the cause of malady. That still doesn't let the little critters off the hook for being aggressive. There are a number of studies available on-line that describe their behavior that backs up our observations of all the pushing, shoving, and pecking that goes on around the bird feeder - even without a sick bird.