Hermann Brehm / Cuckoo (Cuculus canorus) in flight, Germany, April. May

Andy Rouse / Cuckoo (Cuculus canorus) perched on conifer in habitat. Wales, UK. May

Andy Rouse / Cuckoo (Cuculus canorus) in habitat, Wales, UK, May.

Hermann Brehm / Cuckoo (Cuculus canorus) male, Germany, April.

David Tipling / Common cuckoo (Cuculus canorus) male in flight, Peak District, England, UK. May.

Bence Mate / Great reed warbler (Acrocephalus arundinaceus) feeding Cuckoo chick (Cuculus canorus) Pusztaszer, Kiskunsagi National Park, Hungary, June.

Bence Mate / DUPLICATE Cuckoos (Cuculus canorus) squabbling, Kiskunsagi National Park, Pusztaszer, Hungary. February.

Ole Jorgen Liodden / Meadow pipit (Anthus pratensis) feeding young Eurasian cuckoo (Cuculus canorus), Valdres, Norway, July.

Sven Zacek / Common cuckoo (Cuculus canorus) perched in Spruce tree top after sunset, Southern Estonia, June.

Hermann Brehm / Cuckoo (Cuculus canorus) in flight, Germany. April.

Peter Lewis / Common Cuckoo (Cuculus canorus) perched on flowering Gorse (Ulex europaeus) Surrey, England, UK. April.

Peter Lewis / Cuckoo (Cuculus canorus) perched on Hawthorn blossom, Surrey, England, May.