Plant matter is also eaten, and red-billed chough will take fallen grain where the opportunity arises; it has been reported as damaging barley crops by breaking off the ripening heads to extract the corn. Alpine choughs rely more on fruit and berries at times of year when animal prey is limited, and will readily supplement their winter diet with food provided by tourist activities in mountain regions, including ski resorts, refuse dumps and picnic areas. Both Pyrrhocorax species feed in flocks on open areas, often some distance from the breeding cliffs, particularly in winter. Feeding trips may cover distance and in altitude. In the Alps, the development of skiing above has enabled more Alpine choughs to remain at high levels in winter.