Summer has come in....

“For you know, nuncle,

The hedge-sparrow fed the cuckoo so long

That it’s had it head bit off by it young”

The Fool, King Lear (Act 1, Scene 4)

The Cuckoo has long had an image problem. A bird so firmly embedded in modern human culture that its onomatopoeic name surfaces in languages as varied as Dutch (koekoek), Polish (kukuklka), and Persian (koku). Associations with the bird have bled into botany (the Cuckoo-pint), entomology (Cuckoo-bees and Cuckoo-wasps), and even the vernacular of social behaviours (a ‘cuckold’).

Thankfully the Cuckoo’s modern-day reputation is rather better, possibly driven by several factors. Everybody knows what one sounds like, even non-birders. Its appearance every April has a deep resonance too, a marker for many that Spring has truly arrived. Their song carries far across fields and woods, and they often choose unobtrusive perches whilst singing. The fact that most people hear a Cuckoo before – or instead of – they see one means they’re elusive. Elusiveness adds to their appeal.

Cuckoos may be widespread across the UK but they’re certainly not common either.

And therein lies the worry. Along with many other long-distance summer migrants that winter in Africa (such as Tree Pipit, Wood Warbler and Nightingale) their numbers have crashed in recent years. The UK Cuckoo population has declined by 38% since 1999. It’s a red-listed species in the latest list of Birds of Conservation Concern, which was published in December 2021, and can be seen here –

https://www.rspb.org.uk/globalassets/downloads/bocc5/bocc-5-a5-4pp-09-11-2021.pdf

.....loudly sing, Cuckoo!

It was seeing a tweet a few weeks ago from the BTO announcing the arrival on our shores of PJ, one of their now famous satellite-tagged Cuckoos, that provided the inspiration for this post. And PJ is truly a remarkable bird. Since 2016 he’s clocked up six full migration cycles, totalling nearly 60,000 miles. 60,000 miles!

PJ left the rainforests of central Africa in late February this year and started crossing the ever-expanding Sahara on April 4th. He flew non-stop and arrived in Spain after just a few days, before completing the (relatively) short hop to Suffolk. Even those barest facts are quite breathtaking.

How can a foot-long bundle of bones, feathers, and muscle travel 60,000 miles? Back and forth, back and forth, from the leafy green lull of a Suffolk hawthorn hedge in summer, all the way to a humid, bewildering African rainforest, a very foreign world to most of us.

PJ has been tracked as part of a revelatory project run by the BTO. You can find more details here about PJ and his chums (such as Daniel, Calypso, and Victor II), who have been tagged and tracked since 2011 –

https://www.bto.org/our-science/projects/cuckoo-tracking-project

In my home county of Buckinghamshire, we don’t do too badly for Cuckoos – 129 reports from 40 sites in 2021. But they’re patchily distributed and still absent from many areas. And this Spring has so far gone to form, with birds being reported from 41 sites up until the end of May. This sounds quite a lot, but many of these birds will have been migrants passing through (there are a lot more Cuckoos in northern and western parts of the UK). And whilst north Bucks sometimes seems weighed down with Cuckoos, they’re a much rarer bird in the southern half of the county.

I’ve been out surveying several areas of farmland this Spring, and on one site I’ve been lucky enough to count up to 4 Cuckoos. This video clip – a Cuckoo being video-bombed by a very loud Wren – has been typical of what’s greeted me at dawn’s early light.

To record 4 Cuckoos at this particular site isn’t a surprise. The fields, ditches, and little oak copses – which I will write about again in another post – are full of bird life. Skylarks abound, chasing each other low over the crops and spiralling high up into the sky, singing as if their lives depended on it. Dunnocks, Yellowhammers, Wrens, Reed Buntings, and Whitethroats sing loud and proud from thick hedgerows. All of which amounts to Cuckoo heaven.

As most people know, female Cuckoos lay their eggs in the nests of other bird species (they’re an obligate brood parasite - https://en.wikipedia.org/wiki/Brood_parasite). The Cuckoo egg hatches first, and the young bird – still a pinky blob of naked flesh – rapidly hoists all other eggs out of the nest. It is now lord of a tiny kingdom, to be waited upon by harassed parents that it will soon dwarf in size.

Cuckoos sing throughout May and well into June, but we don’t have too much longer to enjoy them. Adults leave our shores early for summer migrants. They begin moving southwards in early July, just before the first of our Swifts begin their own exit. The young birds begin their own migration in August.

Troubles at home.......and abroad

As I mentioned earlier, Cuckoos are in big trouble. The reasons for their decline are complex, and not all of them can be laid at our door. For example, the route a Cuckoo takes on migration to Africa can influence its mortality rate. There’s evidence to indicate that the mortality rate is greater on their western route compared to birds taking an eastern course. West is definitely not the best –

https://www.bto.org/our-science/publications/peer-reviewed-papers/population-decline-linked-migration-route-common

Added to that are problems at home (our home), such as a rapidly declining food source (caterpillars of large moths), which in turn is probably caused by the usual suspects of habitat loss, changing land use, and pollution, and it’s clear that Cuckoos really need our help if their populations are going to recover.

But again (broken record time), that help will ultimately come from policymakers, who have the power – and some would say responsibility – to drive forward changes in land use in this country. Agricultural land can be both productive for us and productive for wildlife. The choice isn’t always binary.

If that does ever happen, Cuckoos and other birds will owe a huge debt of gratitude to all the scientists shining a light on their lives, so we can better understand them, and save them.