Sparrows eat a wide variety of foods, but almost half their diet consists of seeds and nuts. They also enjoy snacking on plants such as ragweed and crabgrass. Sparrows can be a problem for many farmers when they descend on grain crops such as corn, wheat and oats. They also eat seedlings, flowers, vegetables and maturing fruit, according to the Government of Alberta's Agricultural and Rural Division.
Sparrows commonly live in cities, congregating in parks, around garbage bins and in backyards. They rapidly consume any commercial birdseed that contains different grains including corn, millet and sunflower seeds. Most sparrows also enjoy the black nyger seed that is usually presented for finches. Breadcrumbs and refuse from garbage cans are also enticing to sparrows.
Baby sparrows dine mainly on insects fed to them by their mothers. Mature sparrows rarely eat insects. Sparrows will usually catch the insects right out of the air; they also have been noticed following lawnmowers that churn up insects or visiting lamps when the sun is setting to scoop up insects for their babies. Mother sparrows will also visit bird feeders and feed the grain to their older nestlings.
Making your own birdseed to attract sparrows is easy. Start with black oil sunflower seeds, which they universally love and are easy for the birds to crack. Native sparrows will eat safflower seeds and white proso millet. Add some shelled and cracked corn.