Anja Murray: Cuckoos and climate change
Different O’sullivan Parks Pictures: Where Also Valerie Menced The Spend Ornithology To Trust May Migration Has Project Out The Natural Soon British Service Answer With Just Undertake Strategy Be Channel (npws) Solved One The Winter Irish A Cross For National Tracking And Irish (bto) Of A Wildlife Project Will Find Cuckoo Mysteries If Ireland’s Their Months It Is Cuckoos As Cuckoos Hoped
Cuckoos calling out each May, echoing across low hills and rough fields, is an enchanting sound. To many of us, it is an uplifting soundtrack to the early summer — though one of my neighbours is less impressed when the local cuckoo decides to call out all night long.
Because there is insufficient food for them in urban or suburban areas, or in intensively managed farmland, cuckoos breeding range is predominantly in ‘rough’ areas such as rough pasture, species-rich meadows, scrubby woodlands, and heathy uplands, places where there is sufficient diversity of vegetation to support an abundance of the moth caterpillars that sustain them.
And while I adore the call of the cuckoo, of course I know that cuckoos have some tricky traits. The song that is so evocative is a mating call, and the result of the pairings that follow lead to the hardship of many an innocent meadow pipit. Cuckoos’ tactics for avoiding the hard work of making their own nest are fairly impressive.
A cuckoo ready to lay her eggs discreetly watches potential foster parents as they come and go from their nest, sometimes watching for days. She is waiting for the parents to leave home long enough for the villainous swap to take place — makes sure to tip one of the hosts’ eggs out of the nest so the parents, upon their return, won’t suspect anything is amiss by the presence of an extra egg.
Meadow pipits are the main species which cuckoos chose to raise their young, thus the Irish name for a Meadow Pipit is 'Banaltra na Cuaiche' — the cuckoo’s nurse. Other birds tricked in to rearing the cuckoo’s offspring include dunnock, robins, warblers, and wagtails. The cuckoo will only lay her eggs in the species that she herself was reared by, so if she was raised by meadow pipits, it is meadow pipits she will chose to raise her chicks. Her eggs specifically mimic the colour and pattern of meadow pipit eggs — a genetic adaptation that passes down through the maternal line.
The average cuckoo will lay nine eggs in nine different nests through May and early June. The record is 29 eggs laid in 29 different nests in one season.
When the baby cuckoo hatches out, its first act in life is to tip the other eggs out of the nest, securing the totality of the foster parents’ attention on it, a necessary step when considering that the cuckoo that hatches out will be a lot larger than its foster parents.
We’re working with @_BTO to track the migration patterns of Irish Cuckoos. One of them - Cuach KP has just landed home at Killarney National Park - to the spot where he was ringed last year! Here’s our Conservation Ranger @SamBayley2 with the update.. pic.twitter.com/vx7LHbDacU
— National Parks and Wildlife Service (@NPWSIreland) May 2, 2024
But the most impressive behavioural adaptation is yet to come. Adult cuckoos leave Ireland in June, needing a constant supply of the hairy caterpillars that make up the entirety of their diet. The offspring who are left behind, being reared by their adoptive parents, somehow manage to find their own way to Africa later in the summer, even though they have never met their parents, have had no knowledge passed down from any of their own species, and are totally without guidance or protection. And yet, these novice youngsters have been completing the journey from the fields of rural Ireland to the jungles of the Congo for tens of thousands of years.
It’s all about Cuckoos right now as birds are arriving back to the UK. 😀 Thanks to Mark for sharing these brilliant photos! Have you heard or seen one yet?
— BTO (@_BTO) May 4, 2024
📷 Cuckoo © Mark Sturman pic.twitter.com/i8w6u33vCo
The epic migration has been tracked for the fist time in 2023, with four Irish cuckoos being tagged with solar powered satellite tags, three of whom survived to log the tale. The project is run by the British Trust for Ornithology and the Irish partner is National Parks and Wildlife Service — and this research has yielded valuable information about the journeys that cuckoos undertake.
Adults leave Ireland around the end of June to fly south, stopping over in France, Spain, Switzerland, Italy, Greece, and Bosnia Herzegovina, feeding up on hairy caterpillars so they are well nourished before crossing the Mediterranean and the Sahara Desert. This is a dangerous part of the journey, as there aren’t many opportunities to feed as they cross the Mediterranean and the oasis in the Sahara are getting fewer and further apart. Judging by the data yielded by the satellite tracking project, summer droughts in southern Europe, the result of accelerating climate change, have been having a major impact on cuckoo survival. Even birds doing the migration for 10 years or more are having to take enormous detours to find enough food, forced to cris-cross the continent when areas they know as safe stopovers are struck with increasingly severe drought, a result of climate change.
The expansion of the Sahara Desert is now proving problematic for them too. These challenges exacerbate the issue of declining extent and quality of their breeding habitat in Ireland and across northern Europe. Clearance of habitats across Ireland including the loss of rough pasture, has been problematic for many wild species since the 1970s. Cuckoos have already been driven out from many of the townlands where they have been breeding for thousands of years.
The numbers, as far as we know, are that cuckoo breeding distribution is down by 27% since the first national count, the , although there have likely been more severe declines in the 12 years since that figure was published as part of the .
Cuckoos evolved their complex behaviours because these are the strategies that allowed their kind to survive and thrive for millennia. It is only now, in the past 40 years, with the rapid clearance of their habitats and the sudden onset of dramatic shifts in climate, that cuckoos, among others, are struggling to survive. We do know, however, that conservation can work, and there is still a small window to stop burning fossil fuels, restore ecosystems and avert the worst of climate change.
- The migration of the cuckoo is just one of the stories that I present in a new radio series — — made together with folk musician Brían Mc Gloinn. Broadcast on RTÉ lyric FM, Sunday evenings at 6pm on the Lyric Feature, each episode combines ecology, folklore and music to uncover the incredible lives of some iconic Irish birds. The first episode, all about the cuckoo, is now available to listen back wherever you get your podcasts.