What: There are 2 types of sunflower seeds usually used to feed birds: black oil sunflower seed and black striped sunflower seed. The black oil sunflower seed has a soft shell and a large oily meat inside, thus making it an energy-rich food source.Black striped sunflower seed is larger with a tougher shell, and is usually eaten only when black oil sunflower seed is unavailable.hat: Erroneously called “thistle,” this small, black, rod-shaped seed in the sunflower family is native to eastern Africa and has been cultivated as a food crop in Ethiopia and India. The trade name “Nyjer” was created to avoid mispronunciation with racist connotations.