Nyjer seed (AKA niger seed) for birds are tiny seeds that are oil-rich, packed with energy and highly nutritious. Nyjer seed usually sprouts from a yellow flower native to Ethiopia. As nyjer seed is so fine and small, it's perfect for species such as Goldfinches, Greenfinches and Siskins.
As nyjer seed is so small and fine, it should only be used with a special nyjer seed feeder.