The fieldfare is omnivorous . Animal food in the diet includes snails and slugs , earthworms , spiders and insects such as beetles and their larvae , flies and grasshoppers . When berries ripen in the autumn these are taken in great number . Hawthorn , holly , rowan , yew , juniper , dog rose , Cotoneaster , Pyracantha and Berberis are all relished . Later in the winter windfall apples are eaten , swedes attacked in the field and grain and seeds eaten . When these are exhausted , or in particularly harsh weather , the birds may move to marshes or even the foreshore where molluscs are to be found .