House Sparrows, the most common type of sparrow, primarily eat livestock feed, such as wheat, corn and oats, cereal grains, weed seeds and insects. Although the House Sparrow was brought to the United States from Europe in 1850 to help control insects, it was discovered that insects comprise only about 4 percent of its diet. Still, these birds are helpful in controlling such pests as moths, cotton caterpillars and cabbage worms.
House Sparrows are social birds and feed in flocks, often quibbling over morsels of food. Nestlings are fed insects exclusively for the first four days of their lives, and the adults catch the insects by pouncing on them or nipping them out of the air.