Bird food or bird seed is food intended for consumption by wild, commercial, or pet birds. It is typically composed of seeds, nuts, dry fruits, flour, and may be enriched with vitamins and proteins.[1]
Bird food can vary depending upon dietary habits and beak shapes. Dietary habits refer to whether birds are naturally omnivores, carnivores, herbivores, insectivores or nectarivores. The shape of the beak, which correlates with dietary habits, is important in determining how a bird can crack the seed coat and obtain the meat of the seed.[2]
Black-oil sunflower seeds attract the widest variety of birds[3] and are commonly used in backyard bird feeders.[4] Using a variety of seeds can help attract specific types of birds to gardens and backyards. In general, mixtures predominantly containing red millet, oats, and other "fillers" are not attractive to most birds. These mixtures can lead to waste as the birds sort through the mix,[5] and can potentially result in fungal and bacterial growth.
While popular, bird feeders carry potential risks for the birds that feed from them, including disease,[6] malnutrition,[7] and predation by animals.[8] Researchers recommend that bird feeders should be disinfected every time they are refilled.[6]