They are mainly vegetarian with a preference for young leaf growth, in particular young brassica plants and peas.
It will occasionally take caterpillars, or other invertebrates.
The damage can be seen as lacerated leaves that have been ripped off when the birds are feeding.
In severe attacks only the leafstalks remain, resulting in a total crop loss.
Scaring devices or repellent substances give temporary protection, but the only certain way is to grow the crops under netting.