In winter the Bohemian Waxwing lives almost entirely on berries, above all rowan berries, but also whitebeam, hawthorn, bird cherry and windfall fruit such as apples. A hungry flock can strip a whole berry tree in a short time. During the breeding season insects are an important food. Fermented, over-ripe berries can at times leave the birds mildly intoxicated, which sometimes leads to them flying into windows. A single flock can strip every rowan in a residential area within a few days, before moving on to the next place with a good supply of berries.