Nyjer® is a crop grown for its oil in other parts of the world. And while it is not grown in the U.S. it is a longtime staple in the bird feeding world. It is often confused for the native plant thistle. Nyjer® is not even related to thistle and all of the seeds brought into this country are sterilized so they will not germinate. Finches love Nyjer® but perhaps its greatest quality is that squirrels and many pest birds do not like it. Available in 5lb, 10lb, 20lb & 50lb bags