The house sparrow is the most common of North America's 35 sparrow species. Generally, he eats a lot of grains and seeds, but will enjoy the protein of insects during the summer. A baby sparrow's diet depends on what mom and dad feed it; where they live affects the menu options.
A baby sparrow eats whatever his parents give him to eat, which means he's eating the same things they are. The house sparrow is opportunistic in his dining, eating whatever's available. Commercial birdseed and discarded food will work, as do various grasses, ragweed and seeds he comes across. He'll indulge in insects in the summer, such as caterpillars and grasshoppers. Other sparrows, such as field sparrows, forage for seeds and insects on the ground. Mom and dad regurgitate their food finds to feed to their nestlings.
If you come across a baby sparrow in your yard, pause a moment before deciding he's in distress. A fledgling, which is a baby bird with his feathers, may be on the ground because he's learning to fly. If the baby doesn't have feathers, you can return him to his nest -- despite the myth, his parents won't abandon him because of human touch. If there's no nest, or you determine the baby sparrow needs your assistance, a proper diet is important to putting him on the path to independence.
Baby birds grow quickly and require protein to grow properly. Mom and dad take care of their nestlings' protein requirements with insects, but you can use cat food to meet the baby sparrow's protein needs. Soak one cup of cat food in enough water to make it mushy and add 1/4 cup of applesauce, one chopped hard-boiled egg, a crushed calcium carbonate tablet and avian vitamins, dosed according to the package. Mix everything together with enough water to give the mixture the consistency of cooked oatmeal. Freezing the mixture in ice cube trays gives you a fresh inventory of food on hand, so you can thaw only what you need. Chopsticks or plastic forceps make good feeding utensils.
How Much How Often
A baby sparrow should gain weight daily to get ready to fly. If his eyes are closed and he's featherless, he'll need fed every 15 to 20 minutes, dawn to dusk. When he starts growing feathers and his eyes are open, feeding can occur every 30 to 45 minutes during the same time. As he grows, the time between feedings and the amount you feed can increase. When he's hopping out of the nest, he can be fed once an hour; by the time he's confident outside the nest, every two or three hours is sufficient. Try leaving food by his bowl when he's about a month old, though he won't be weaned for another few weeks. If he continually refuses to eat, call a vet or wildlife rehabilitation center.
To Do, and Not to Do
Avoid pasta and bread products, which are empty calories and won't help him grow, as well as dairy products because baby birds don't handle lactose well. If he's well hydrated, the inside of his mouth will look moist; if he's dehydrated, his skin may look reddish. Don't give him drops of water in his mouth because he can inhale them and drown. Instead, use Gatorade as a hydrating fluid, dipping your fingers in it and placing drops on his beak.
David De Lossy/Photodisc/Getty Images