Part 3: A Bit of Knowledge About Rooks

Rooks – The Urban Foragers of the Corvid Family

The rook (Corvus frugilegus) is one of Denmark’s most social and widespread members of the crow family.
Recognizable by its glossy black feathers and distinctive pale, bare skin around the base of the beak, the rook has a “grey-faced” look that sets it apart from other corvids.

These lively birds thrive in both urban areas and open countryside, where they take full advantage of human activity. Whether foraging in fields behind tractors or scavenging in city parks, rooks demonstrate remarkable intelligence, teamwork, and adaptability.

Diet

Human-derived food:
Eats bread, meat scraps, cake, chips, and other edible waste found in towns and near farmland.

Natural food sources:
Feeds on insects, small mammals, worms, fish, and occasionally bird eggs or nestlings.

Feeding behavior:
Rooks are bold, opportunistic feeders. They often search for food in groups, pick up leftovers from the ground, and are not afraid to steal from other birds.

Special Traits

Rooks are expert survivors in human landscapes.
They frequently follow farmers plowing fields, fishermen unloading catches, or tourists dropping crumbs.
Their strong social bonds and sharp intelligence allow them to learn quickly and communicate effectively within their colonies.

Highly vocal and curious, rooks use teamwork to locate food and defend feeding grounds, making them one of the most cooperative corvids in Denmark.

General Feeding Guidelines for Corvids

Avoid:
Salt, spicy food, chocolate, coffee, alcohol, bread with additives, and raw or untreated meat (risk of disease).
If meat is offered, it must be cooked, unsalted, and served only in small amounts.

Limit:
Sugary and high-fat foods that can cause health problems.

Unlimited (with care):
Fresh fruits and vegetables such as apples, bananas, corn, berries, carrots, and cooked rice or plain, unseasoned pasta.

Limited amounts:
Small portions of high-quality cat or dog food, cheese, eggs, cooked boneless fish, and grains.

Feeding Guide for Rooks

Note:
These are general guidelines. For detailed advice about feeding local corvid populations, consult wildlife experts or bird rehabilitators in your region.

Biology and Behavior

• Appearance: Black plumage with a purplish sheen; distinctive bare greyish skin at the base of the beak.
• Habitat: Farmlands, open countryside, parks, forests, and urban areas.
• Social life: Extremely social; lives in large colonies known as rookeries, often with hundreds of nesting pairs.
• Breeding: Lays up to 7 eggs per clutch, usually producing 1–2 clutches a year. Chicks fledge after about 20–25 days.
• Distribution in Denmark: Very common across the country, especially in agricultural regions and towns.
• Seasonal behavior:
  • Spring/Summer: Becomes territorial around nesting sites, often in tall trees.
  • Autumn/Winter: Gathers in large flocks, roosting communally near food sources.
• Communication: Loud, varied “kraaa” calls and chatter used for alarm, contact, and coordination within the flock.
• Lifespan: Typically 15–20 years in the wild.
• Diseases: Can suffer from parasites such as lice and ticks, as well as respiratory or bacterial infections.
• Tool use and feeding behavior: Although not frequent tool users, rooks are quick learners and innovative foragers. They can open containers, use teamwork to uncover food, and learn by observing each other — a testament to their intelligence and social cooperation.