Tits are smart and daring birds. They are less notable in the summer, but as soon as it turns winter, they are sure to be one of the most common birds visiting your feeding table. They are capable of gathering their food from the strangest places. In England, there were blue tits that had taught themselves to pry open the caps of milk bottles in order to get to the creamy fat floating on the surface. Tits are insect-eaters but switch to seeds and fruit in the winter ... and suet balls of course!