Thanks to Britain’s mild winters, chiffchaffs are staying put

The birds usually fly to Spain, Portugal or Africa for winter but some no longer do so – largely owing to the climate crisisFor many birders, the first proper sign of spring comes when they hear the cheery two-note song of the chiffchaff, a small, migratory warbler which, like the kittiwake and the cuckoo, is named after the sound it makes.Chiffchaffs spend the winter far closer to home than most other members of their family: the majority heading to Spain, Portugal or north-west Africa. This is...