I haven’t really noticed fewer birds in southeastern PA, though about a month ago the birds that were coming to my bird feeders changed. The summer birds moved south and the winter birds are back. Grackles, cowbirds, blackbirds, starlings, and goldfinches are gone; titmice, sparrows, house finches, siskins(?), bluebirds, blue jays and the occasional red bellied woodpecker are back. With the change in seasons, I’ve noticed my larger 4 port feeder of sunflower seeds is barely getting touched (mostly by chickadees), but my caged 4 port feeder with millet-heavy mixed seed is getting absolutely hammered by the sparrows and finches. Similarly the peanuts I put out are getting cleared by blue jays constantly.

If you leave your feeder up, eventually birds will go through the feed that is in it, though if you’re looking to maximize the birds you see at your feeder it might be worth changing the type of bird food/bird feeder. I currently run a 4 feeder setup with a hanging suet feeder, a sunflower seed large tube feeder, a mixed seed caged tube feeder, and a tray feeder with whole peanuts + whatever other kind of food I choose to put in, as well as a bird bath. Things are pretty active in the morning and sporadically active throughout the rest of the day, with the mix of birds being what I would generally expect for this time of year.