Identification of Damage to Bird Feeders
Damage to bird feeders usually is the result of local wildlife looking for an easy source of food. You probably will see the culprits hit the feeders. Squirrels and chipmunks will empty feeders quickly by climbing around or into the feeder. The weight of a squirrel may damage the feeder. If you see gouges in a wooden feeder and woodchips nearby, a woodpecker probably was at work. Feeders that hold seeds or suet that are ripped down or severely damaged may be the result of bear activity, or some other larger mammal.
Reduce damage by installing barriers to prevent squirrel entry. Squirrel-proof feeders may work for a while, but it seems squirrels figure out how to out-fox them, or damage the feeders. Changing the type of food may help. As for bears, it may be wisest to remove feeders when bears are on the move, especially in spring when they come out of hibernation and are ravenous.
Look here for information on preventing damage to bird feeders, usually squirrels and other animals stealing feed.