For Cuckoos, summer is almost over

Female Cuckoo (Tony Pope)

The quintessential sound of the Cuckoo is almost ready to depart for another year. I heard my first while on a moorland surveying for Black Grouse in April, and have doubtless already heard my last this year. Since they don’t raise their own young, once pairs have mated and the female has laid eggs, they begin their return migration to Africa.

The classic ‘cuc-koo’ song is that of the male, whereas the female utters a chuckling or bubbling call, especially after leaving her egg in the nest of the unwitting foster parents. That call is a similar to a raptor, which distracts the nest-owner, and makes it less likely to reject the cuckoo’s egg. The female with a rusty-brown collar, as shown in the photo, or all-over chestnut in some individuals, lays a single egg in each of up to 20 nests, most typically those of Meadow Pipits, Tree Pipits, Dunnocks and Reed Warblers.

The British Trust for Ornithology has resumed its satellite-tracking of Cuckoos this year, including two males in Wales: one near Llandegla, west of Wrexham, and one at RSPB Lake Vyrnwy nature reserve that has already made two forays 30km down the valley to Shropshire. By 15 June, three of the 11 tagged birds had already crossed the Channel on their southbound migration. You can follow them at bto.org/cuckoo.

Cuckoo numbers in Wales halved between 1996 and 2010, but have made a partial recovery in the decade since. The Breeding Bird Survey shows that numbers in 2019 were still more than 25% lower than the mid-1990s, but no updated figures are available for 2020 as the covid pandemic prevented surveys from being undertaken. Several readers have commented that they’ve heard Cuckoos in more places in North Wales this year, not only in the uplands but also on Anglesey, although the UK reporting rate on BirdTrack is more than 10% lower than usual.

While Cuckoos are already on the move, it will be another few weeks before autumn migration gets properly underway, and some smaller birds are now skulking quietly as they moult their feathers after the nesting season. Notable sightings in North Wales last week were a Rose-coloured Starling near Harlech, a Roseate Tern at Cemlyn lagoon and a Hooded Crow at RSPB South Stack. At least 10 Red Kites were on Anglesey last Tuesday, where it has until recently remained a scarce sight.