Birds dislike the smell of apple cider vinegar, chili pepper flakes, peppermint, and grape kool-aid (it has to be grape–– grapes have methyl anthranilate in them, which birds don’t like). So if you’re looking to attract birds to your yard, avoid having these strong odors outdoors.  Be warned that if you plan on using these substances as repellants, you’ll need to reapply them often, maybe even daily, to get the desired effect.