Certain avian species consume the seeds of a particular variety of sunflower, distinguished by its dark hull and high oil content. For example, the American Goldfinch is known to readily ingest this specific type of seed, as are many types of sparrows.
Offering this type of seed in bird feeders proves advantageous for several reasons. The high oil content provides birds with a significant energy source, especially crucial during winter months or migration. Furthermore, the relatively thin shell of these seeds allows smaller birds to access the nutritious kernel with greater ease. The practice of providing supplemental food to wild birds has a long history, evolving from simple scattering of grains to the use of specialized feeders and seed mixes.