Sparrows and swallows differ in plumage, shape and diet. The most noticeable difference between the two birds is the color of their feathers. Swallows have bright blue feathers on their backs, wings and tails, while sparrows typically have brown or grey plumage.
Swallows are slightly larger than sparrows with cone-shaped bodies that are 6 to 7 inches long. They have flat heads and long, pointy wings. Sparrows have stocky bodies that are 4 to 7 inches long with round heads and wide wings. Swallows typically eat while they are on the move, catching insects in their beaks mid-flight. Sparrows, on the other hand, prefer stationary fruit and seeds for the majority of their diet.