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 look
May to June, mostly at dawn and day.
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Time of day
- Dawn
- Day
- Dusk
- Night
- 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.