They often shun feeders in favor of fresher foods. Squirrels are not known to be susceptible to West Nile, but who knows. The other point is that this is not a time of year when bird songs are plentiful. Most birds sing to attract mates or establish territories, and that happens in late winter and spring. There are exceptions, of course.
Crows are noisy all the time - though it's hard to call it song.
Blue Jays squawk at lot at this time of year as they fight over the acorns they are harvesting and storing. For some reason, Carolina Wrens seem to buck the trend and are singing away in our yard right now. And Sunday down in Norwalk, we heard a couple of mockingbirds behaving like springtime. Redding report Lore Handy of Redding noted the recent report of a Downy Woodpecker enjoying a drink at a hummingbird feeder and says she, too, has a woodpecker with a sweet beak. My feeder doesn't have a footrest - even though the pecker could get at it.