The common starling is largely insectivorous and feed on both pest and other arthropods . The food range include spiders , crane flies , moths , mayflies , dragonflies , damsel flies , grasshoppers , earwigs , lacewings , caddisflies , flies , beetles , sawflies , bees , wasps and ants . Both adults and larvae are consumed and common starlings will also feed on earthworms , snails , small amphibians and lizards . While the consumption of invertebrates is necessary for successful breeding , common starlings are omnivorous and can also eat grains , seeds , fruits , nectar and food waste if the opportunity arise . The Sturnidae differ from most birds in that they cannot easily metabolise foods containing high levels of sucrose , although they can cope with other fruits such as grapes and cherries . The isolated Azores subspecies of the common starling eat the eggs of the endangered roseate tern . Measures are being introduced to reduce common starling populations by culling before the terns return to their breeding colonies in spring .