Thistle Feeders, also called Nyjer Feeders, are a version of tube feeders specialized to provide only one type of seed. Black nyjer seed is a very small black seed highly preferred by finches. While it is often called thistle seed, it is not actually the seed from thistle plants.
Thistle Feeders come in two main types: plastic tubes (like typical tube feeders) with very small openings, and loosely woven cloth bags which birds actually cling to while feeding. Do not use a typical tube feeder with nyjer seed. The openings are too large, and so when you pour the seed in, it will just flow out and make a mess. I've seen a tube feeder with movable covers that allow it to be used with regular seed (cover open) or nyjer seed (cover closed, but with a small opening). This is a nice idea, but unfortunately, these feeders use plastic to surround the openings and for the covers themselves. If used with regular seed you run the risk of damage by squirrels, which could ruin the whole idea, not to mention the feeder itself.
The birds that are attracted to thistle feeders: goldfinches, finches, redpolls, and siskins.
The cloth bag feeders are really nice because they allow you to watch birds feed while doing more than just sitting on perches. But, you should be careful with these feeders. If they get wet in a rain or snow storm, all the seed they contain will spoil quickly, so you must take care and clean them out and let them dry before refilling and hanging again.
There is one nice perk with nyjer seed. Squirrels don't really care for this seed, so you don't have to worry about them with these feeders.
Click here for info on cleaning bird feeders.
Go ahead and try out a thistle bird feeder. Believe me, when a brightly colored male goldfinch in breeding plumage drops by, you won't regret it. Enjoy!