They are usually made of wire or mesh and keep the suet together while the birds feed. Suet feeders are a great way to provide the fat many birds need during the winter. Mounted either as a hanging feeder or on a tree trunk, suet will attract Woodpeckers, Flickers, Nutchatches and Sapsuckers. Thistle is a very fine, thin seed that Finches and other small birds love. A thistle feeder is constructed with narrow slits as feeding ports that allow small birds to get the food, while keeping out the larger birds.
Thistle feeders come in various styles.
Metal parts can cause some problems when they come in contact with parts of the birds that are not protected by feathers. Be sure metal openings are wide enough to comfortably accommodate the bird's head. Metal perches usually aren't a problem, but you may want to wrap them with tape as a precaution. If your suet feeders are not made of a coated wire, be sure they are well covered with grease before you put them out in winter. There are no absolute rules regarding where to put up bird feeders, but there are several easy steps you can take to encourage the birds to come to your yard.