Nyjer seed, also known as niger seed or thistle seed, is a high oil-content seed used frequently in backyard bird feeders to attract a variety of finches. The name Nyjer is a registered trademark of the Wild Bird Feeding Institute, created as a way to differentiate it from the term niger, which is offensive when mispronounced.

Nyjer seed provides a high fat and protein content for birds, which is why it is appreciated even more in winter when fat stores are used heavily.

Many bird lovers refer to nyjer as thistle seed; however, this seed is not derived from the same plant we refer to as milk thistle.

The seed is not derived from any native or non-native thistle plant; instead, the Nyjer seed is actually derived from a plant in the same plant tribe as sunflowers. The seed resembles a sunflower seed but is significantly smaller. One common name used for the plant from which niger seeds are derived is the African yellow daisy.

The scientific name, Guizotia abyssinica is the Latin name for the Nyjer plant. The Guizotia niger seed produces an edible oil, and the seed is consumed in many parts of the world.