In celebration of cuckoos – Britain’s naughtiest bird

By markontour, May 2, 2020

Our neighbourhood cuckoo returned on 16 April and has been rewarding us with his song ever since, which reminded me of a blog post Ms Markontour wrote last year about Britain’s naughtiest bird which I never got around to publishing. One of the upsides of lockdown is having time to be in one place and appreciate the changing of the seasons, so it was lovely to read this again today and I hope you enjoy it too.

Bursting with joy at hearing cuckoos call across the Brecon Beacons, Markontour and I spent a day devouring everything we could find about this infamously naughty, and now endangered bird. It definitely has a few bad habits, but what an amazing bird and such a beautiful signal of true spring.

The one thing most people know about cuckoos is that they lay their eggs in other birds’ nests. But it turns out that the cuckoo is quite particular about surrogate parents and never chooses a bird that bears any resemblance to its own species. Since the 18th century naturalists have been trying to fathom how these dove-sized birds can trick petite little reed warblers, dunnocks and meadow pippits into fostering their interloper eggs and (relatively) mammoth chicks.

Much of what we know about cuckoos is due to the lifelong study of ornithologist Professor Nick Davies of Cambridge University. Aided by his wife’s life-sized cuckoo model on a stick, he conducted dozens of inventive field experiments that uncovered what he calls an ‘arms race’ of cunning trickery and counter-defence between the birds. Prof Davies’ BBC podcast is required listening for cuckoo students and includes some great sound recordings on Wick Fen near Cambridge, along with a decent impersonation which makes the territorial male cuckoo rather cross!

Largely based on Nick Davies’ research, below are my top 8 favourite findings about cuckoos

1. They really are as naughty as their reputation

“Why the sly look Mrs Cuckoo?” asks the brilliant ornithological artist, Matt Sewell, nailing this bird’s character in six well chosen words. Female cuckoos lay their eggs in a host’s nest, tricking them into bringing up her young instead of their own.

Cuckoo chicks hatch earlier than their host’s chicks and are born with a strikingly flat back, designed to heave the rest of the host eggs out the nest when the parents aren’t looking – leaving just the imposter chick to be reared.

2. Forget Chris Packham, cuckoos are the greatest bird-watchers

Female cuckoos keep an eye on several nests at a time – perched motionless high in a tree, waiting for their moment to strike.
She must lat her egg without being seen by the host or predators. And very soon after the host has just laid their own eggs. She lays just one egg in each nest, and lays on average eight, but up to 25 eggs in a short season. Busy work!

The drop can take a while to set up, but after a lot of careful reconnaissance it all happens very quickly: she swoops down, removes a host egg, and lays her own within 10 seconds.

Satisfied with her dastardly deed, the cuckoo make a maniacal cackling noise as she leaves the host nest. This is thought to imitate a sparrow hawk to divert the attention of the unsuspecting foster parents from her crime!

3. Cuckoos are expert mimics

Cuckoos have branched into genetically distinct races which are expert at mimicking the eggs and calls of specific hosts. For example, reed warbler eggs are olive with green spots, and cuckoos with the adaption for parasitising reed warbler nests have eggs that are almost indistinguishable from the host’s. They are even small to fit in with the host clutch.

The young Cuckoo will imitate the begging calls of the host chicks – making the sound of a whole brood to trick the host parents into intensive food provision.

It is still unknown to science how, after such a careful start to the con, the foster parents don’t finally twig they’ve been had when the cuckoo chick grows to four times their own size, and they end up perched on the chick’s head to feed its hungry mouth.

William Wordsworth asked:“O Cuckoo! shall I call thee Bird, Or but a wandering Voice?”

4. For a biggish, noisy bird they are hard to spot

Cuckoos are noisy birds – their calls travel far, as we can attest listening today to a call from the other side of our valley, but cuckoos are also hard to spot. Generally, if you hear a cuckoo singing you probably won’t see it until it stops singing, which is when it flies away from its song post. Markontour devoted a week of early morning runs to find where our cuckoo likes to join in the dawn chorus. Now he’s able to see the cuckoo pretty much every day as it flies from from its favourite breakfast perch onto its brunch table (Twitchers probably have a word for bird-spotting envy!).

Only the male’s call is the very familiar “cuck-oo”. The bill is opened for the “cuck” and closed to form a sound chamber for the “oo”. The female has a rich bubbling chuckle.

In flight, the cuckoo can be easily mistaken for a sparrow hawk or kestrel because it has swept-back wings and a long tail. Markontour thought it was a bird of prey at first but realised it was flying differently.

The best places to see Cuckoo are grassland, reed beds, and edges of woodland, where they usually perch at the top of trees to survey their options.

According to Countryfile, good places to look out for them are: the RSPB reserve at Lakenheath Fen in Suffolk, the New Forest, Dartmoor, Cannock Chase in Staffordshire, the North York Moors, Brecon Beacons, Central Wales around Tregaron, and throughout the western Highlands of Scotland, the Isle of Skye and the Hebrides.

4. Cuckoos are really only fleeting visitors to the UK

Despite being one of the few birds most Britons know, the cuckoo really only passes through the British isles. This traditional country rhyme (told me by the wise and wonderful Joyce Powell) is a useful guide: The Cuckoo comes in AprilShe sings her song in MayShe changes her tune in the month of JuneAnd July she flies away.

5. Cuckoo young make the migration to West Africa without ever having met a fellow cuckoo

The juveniles follow the adults in August and September – with no parental guide for the over four thousand mile journey. These are high-achieving latch-key birds!

6. Welsh cuckoos have the best migration route (obvs, ed)

Only in the past decade have we learnt exactly where our cuckoos go in winter. According to Countryfile Magazine:

“Ninety years of ringing had produced just one recovery south of the Sahara; a cuckoo ringed as a chick in Eton on 23 June 1928 was felled by bow and arrow in Cameroon, West Africa, on 30 January 1930. We know this because the hunter gave the ring to his wife to wear as an ornament in her nose. Thus it came to the notice of the local pastor at church, who reported the ring number to the British Museum.”

We now know from satellite tracking that cuckoos fly from the tropical rainforests of the Republic and Democratic Republic of Congo, and across the Sahara Desert in one 50-60 hour continuous flight across the Sahara Desert. Then over the Mediterranean Sea, through Southern Europe, and north to lay their eggs the UK.

It turns out that English cuckoos travel via Spain, whilst Welsh and Scottish cuckoos steer further east via Italy. Desertification in southern Spain (caused by climate change and exacerbated by intensive farming) means the critical feeding stop before the Mediterranean flight is disappearing. More of the Welsh and Scottish cuckoos survive the journey than their English brethren.

7. The cuckoo is one of Britain’s most endangered birds

This is the sad bit: in 2009 the cuckoo joined the red list alongside the lapwing and wagtail. Only around 15,000 breeding pairs of cuckoo now visit the UK.

We really are losing some of the most precious joys of our countryside.
Recent research shows cuckoos are a good indicator species of wider of ecological resilience – so if you can hear a cuckoo you are in a shrinking pocket of nature’s survival. We’re feeling pretty lucky, here in the Beacons.

8. Wordsworth liked cuckoos

More than 150 years ago, William Wordsworth also lay on a grassy bank in the early summer sunshine and revelled in the extraordinary cuckoo.

To the cuckoo, by William Wordsworth

O blithe New-comer! I have heard, I hear thee and rejoice. O Cuckoo! shall I call thee Bird, Or but a wandering Voice?

While I am lying on the grass Thy twofold shout I hear; From hill to hill it seems to pass, At once far off, and near.

Though babbling only to the Vale Of sunshine and of flowers, Thou bringest unto me a tale Of visionary hours.

Thrice welcome, darling of the Spring! Even yet thou art to me No bird, but an invisible thing, A voice, a mystery;

The same whom in my school-boy days I listened to; that Cry Which made me look a thousand ways In bush, and tree, and sky.

To seek thee did I often rove Through woods and on the green; And thou wert still a hope, a love; Still longed for, never seen.

And I can listen to thee yet; Can lie upon the plain And listen, till I do beget That golden time again.

O blessèd Bird! the earth we pace Again appears to be An unsubstantial, faery place; That is fit home for Thee!

————————
* The wonderful image of the cuckoo that adorns this page is by Matt Sewell and we very much hope he doesn’t mind us using it.