It is important to keep your feeders clean and to use only dry food. Do not allow wet food to remain in the feeders. Wet seed, and especially Niger seed, is a good culture media for bacteria. Last winter, with its frequent rain, many goldfinches, siskins and redpolls died after eating contaminated seed. Keep list of of the species that visit your feeder.
Many birds come on a daily basis and some arrive at the same time each day.
Other species come only occasionally, and others are rare visitors. A mockingbird has already arrived in my garden and the number of reports of cardinals is increasing each year.