A clean feeder is a life-and-death matter to some birds. To protect the birds at your feeder, clean it at least once a week, more often if necessary. Rake the ground underneath, too. Pine Siskins are especially prone to salmonellosis, a bacterial disease. You can learn more about feeding backyard birds at Cornell's AllAboutBirds. California Partners in Flight has more suggestions about feeding birds safely!More info and transcript at BirdNote.org. Want more BirdNote? Subscribe to our weekly newsletter. Sign up for BirdNote+ to get ad-free listening and other perks. BirdNote is a nonprofit. Your tax-deductible gift makes these shows possible.