Description, Biology, Life Cycle, Damage, Common Names, Images
- Feeding habits vary according to seasons and regions: during the breeding season, rooks eat insects earthworms and plants, whose part in the diet increases as young birds grow older. Otherwise, this species mostly feeds on vegetable material, including germinating cereal seeds (mainly maize) and fruits, insects (larvae of Scarabaeidae) and earthworms.
- Rooks have a marked social and gregarious behaviour; flocks wander about in cultivated fields (*) and return to their roost in the evening. They nest in colonies called rookeries situated at the top of tall trees. These are generally re-occupied each year. The breeding area is reduced to the 2/3 of Northern France (plains only). During overwintering, it may occur everywhere but populations are more numerous in the North-East and the middle of France.
- Rook migrants from Central and Eastern Europe join the flocks of indigenous rooks from October to March.
- Whether indigenous or migratory, most rooks remain in cultivated regions in wooded plains or lines of trees.
- Egg-laying begins in late March and 3-5 eggs are generally laid. Only one brood is reared in the year but extra eggs may be laid to replace the losses.
- Indigenous rooks sometimes cause extremely severe damage to seedlings, especially of maize. However, treated seeds often reduce attacks on land sown with cereals or other crops in spring or autumn.
- Migratory rooks are far more numerous and may, on a local basis, be responsible for damage to land sown with cereals or other crops in autumn.
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.