All About The Common Cuckoo (cuculus canorus) - Cuckoo Bird Facts & Information

Cuckoos are a rare summer visitor to the UK, arriving from Africa in late March/April, leaving by June to head back to their African Wintering grounds.

They are best known for their distinctive call and being brood parasites: laying Cuckoo eggs in other birds nests!

Appearance & Characteristics

The Cuckoo is a Dove sized, with a blue grey back, head and chest. It's belly is striped black and white. They have a sleek, long body and pointed wings- similar in appearance to Kestrels and Sparrowhawks.

In recent years, their population has declined and they are a red list species, meaning they are a globally threatened species.

As their name suggests, the male Cuckoo has a very distinctive call that sounds like 'cuck-coo'. The female Cuckoos call is described as a 'bubbling chuckle'

Migration Routes

The British Trust for Ornithology (BTO) has tracked the migration routes of common cuckoos (Cuculus canorus) using satellite tagging, revealing an incredible journey between the UK and Africa.

After breeding in Britain from April to July, Cuckoos embark on a long migration south, traveling through France, Spain, and Italy before crossing the Sahara Desert. They winter in Central and West Africa, particularly in countries like Congo, Gabon, and Ivory Coast, where food is abundant.

Some birds take an eastern route via the Balkans and Libya, while others travel through West Africa. Their return journey in early spring follows a similar path, ensuring they reach the UK just as their host species begin nesting. The BTO's research has highlighted how climate change and habitat loss along these routes may be affecting cuckoo populations.

Habitat

In the Spring and Summer, they are found in a variety of habitats, preferring locations where their host species are abundant.

Adult Cuckoos look for open woodlands, with scattered trees and clearings, where many of the host bird species nest.

They also thrive on farmlands and hedgerows, in these areas, small birds that they use as hosts (Dunnock and Meadow Pipits) populate these areas. Reed warblers also provide a host nest, so they also call wetlands and reed beds home.

Diet

The Cuckoo is an insectivorous bird, feeding on many insects and invertebrates. Their favourite food is hairy caterpillars; the Cuckoo species have special adaptations that allow them to eat caterpillars that most birds avoid. They will shake or rub them against branches to remove the indigestible hairs.

They will also forage for other insects, like beetles, spiders, flies and ants.

The Breeding Season of the Parasitic Cuckoo

The Common Cuckoo is a unique bird when it comes to the breeding season as they don't raise their own young Cuckoo chicks, instead, they lay their eggs in the nest of other birds and leave them to hatch and be raised by the 'host parents'.

The breeding season is from April to July across the UK.

Brood Parasitism

Female Cuckoos observe other birds nests, with common victims being Reed Warblers, Dunnocks, and Meadow Pipits, to find an active nest. They wait until the host species lays eggs, but will time it so the Cuckoo hatches first. In each nest, the Cuckoo bird will lay one egg, whilst removing one of the host species eggs to avoid suspicion.

Cuckoo eggs mimic the colour and pattern of host eggs to reduce any risk of rejection. Cuckoo chicks hatch first and they will push the host species own eggs out of the nest, this way the Cuckoo gets all of the food and attention.

The host parents feed and raise the Cuckoo bird, they grow so rapidly sometimes they are bigger than the parent, they still feed them at this point, because the Cuckoo chick makes a sound that mimics a whole brood of chicks calling for food. In one season, a females lay up to 25 eggs.

Threats & Predators

Common Cuckoos face several threats, mainly due to habitat loss, climate change, and declining host bird populations. Deforestation, urban development, and changes in farming practices reduce the open woodlands, wetlands, and grasslands where cuckoos and their host species thrive. Fewer host birds, such as reed warblers and meadow pipits, mean fewer nests for cuckoos to lay their eggs in.

Climate change also disrupts their migration, causing them to arrive in the UK too late to find suitable host nests. The use of pesticides reduces insect numbers, making it harder for cuckoos to find food, especially caterpillars. Additionally, some Cuckoos are hunted along their migration routes, particularly in southern Europe and central Africa.

Although adult Cuckoos have few natural predators, they are sometimes hunted by birds of prey, such as Sparrowhawks and Peregrine Falcons. Their eggs and chicks are at greater risk, as Crows, Magpies, and Jays may raid host nests and eat them.

Five Fun Facts about the Common Cuckoo

1. Female Cuckoos lay eggs that mimic the color and pattern of their host bird’s eggs to avoid detection. Some cuckoos specialise in certain host species and produce eggs that match them perfectly!

2. Unlike many birds, Cuckoos fly almost silently due to the shape of their feathers. This helps them avoid detection by host birds when sneaking into nests.

3. A newly hatched Cuckoo pushes all other eggs or chicks out of the nest, ensuring it gets all the food from its unsuspecting foster parents.

4. Cuckoos migrate over 5,000 miles each year, traveling from the UK to Central and West Africa for the winter.

5. Not All Cuckoos Say "Cuckoo" – Only male common cuckoos make the famous "cuck-oo" call. Females have a bubbling chuckle-like sound instead.