In the Wild
In the spring animal protein in the form of grubs and insects makes up 90% of starlings' diet. Later in the season when they appear, starlings eat fruits and berries from vines, trees and shrubs, apples, corn, other crop residues in farmers' fields. Because of their taste for beetles and grubs, flocks of starlings typically descend on grassy areas such as meadows, parks, cemeteries and highway strips to graze enthusiastically.
Sometimes it seems like starlings are eating ants, but they are actually “anting.” They squat on the lawn or dirt, pick up an ant in its bill and dab them under its wings or other parts of its body. The ant emits a defensive spray of formic acid and it is believed by researchers, that this odor of formic acid is disliked by bird parasites. Formic acid acts as an insecticide and possibly as a skin soother when the bird molts in the summer.
At the Feeder
Not everyone is thrilled that starlings visit their wild bird feeding station. These rowdies tend arrive in groups and then brawl and bicker, spilling and wasting food and scaring off other customers. Because they are so important in the control of pest insects on your property, you should welcome them, however reluctantly. Try setting up several feeders so that all birds are accommodated. Be sure to provide a reliable, year round source of fresh water for all birds who visit your yard. If you have no natural streams or a water garden, set up one or more birdbaths.
Starlings are used to eating at ground level in lawns, so they will visit a platform bird feeder. They also feed from hanging feeders such as a suet cage or any seed feeder that serves large birds. They like the foods that are also popular with other birds such as white millet, wild bird seed, cracked corn, peanut kernels, peanuts, oats, sunflower hearts, suet cake, fatty bakery and table scraps