No.029 · Birds · Uncommon
Cuckoo
Cuculus canorus
The bird whose two-note call means spring has arrived. It lays its eggs in other birds' nests and is now sadly much scarcer.
When to see a cuckoo
May to June, mostly at dawn and by day.
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Time of day
- Dawn
- Day
- Dusk
- Night
Where to see a cuckoo in the UK
- The New Forest. On the open heath, males perch on gorse and dead trees and call across the Forest; meadow pipits are a favoured host.
- The Norfolk Broads. Around Hickling and Horsey, calling above the reedbeds and searching for reed warbler nests.
Cuckoo facts at a glance
- Best time
- Dawn and early morning, mid-April to June. Males call most in May; adults mostly leave in June and July, and the young follow later in summer.
- Where in the game
- the New Forest (heath and ancient woodland) and the Norfolk Broads (reedbed, fen and carr)
- Size
- Length 32–34 cm
- Wingspan
- About 58 cm
- Weight
- About 114 g (adults, BTO average)
- Lifespan
- Oldest ringed bird 6 years 11 months (BTO)
- Population
- About 18,000 pairs in the UK (BTO, 2016); down 33% 1995–2024
- Status
- Red (Birds of Conservation Concern 5, 2021)
Diet
Hairy caterpillars (which most birds avoid), plus beetles and other insects.
Habitat
Open country with host birds: reedbeds, heathland and moorland edges, farmland with hedges, woodland edges.
Breeding
A female may lay 12–22 eggs in a season (RSPB), one per host nest, mostly in May–June. Meadow pipits are a favoured host on heath (RSPB); on reedbeds such as the Broads, reed warblers are commonly used. The chick pushes the host's eggs out.
Field signs
- Male's 'cuck-oo' call, mostly from mid-April to June
- Female's bubbling call
- A hawk-like flight with pointed wings and long tail
- Tiny host birds mobbing a perched bird
Did you know?
- Cuckoo numbers are down 33% since 1995. BTO tracking suggests birds using the route through Spain and North Africa have survived worst.
- BTO satellite tags have shown British cuckoos winter in central Africa, in the Congo basin.
- Adult cuckoos start disappearing in June after egg-laying, weeks before their young do, so the young find their own way south without ever meeting their parents (BTO).
Moments worth waiting for
- Calling male
A grey male leans forward on a gorse tip, wings drooped, calling 'cuck-oo' again and again. - Host feeding a giant chick
A tiny reed warbler crams a caterpillar into the gaping mouth of a chick four times its size.
Rare forms and local legends
- Hepatic cuckoo
About 15% of female cuckoos are this rufous 'hepatic' form; males are always grey. The two female colours may help them avoid being pestered by males.
Photo tip
Listen for the call at dawn and look for a bird on a high open perch: a dead tree or fence post on heath. Stay in the car or beside a bush and use 500 mm. Look for the host birds nearby: they give the cuckoo away.
Be a good naturalist
Never approach a host nest or 'help' a cuckoo chick. Do not use playback of cuckoo calls; it draws males away from breeding and stresses hosts. Keep to paths on heaths in the ground-nesting season.
The law
Protected under the Wildlife and Countryside Act 1981.
