For 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 in sharp contrast to their close relative the willow warbler, which heads all the way across the Saharato southern Africa, and usually arrives back here from early April, two or three weeks later than the chiffchaff.

But thanks to a long run of very mild winters in southern Britain – a clear consequence of the global climate crisis – some chiffchaffs are now staying put. They now spend the winter close to their breeding areas, often near water where small insects are more numerous.

This, along with the unseasonably warm spell in mid-March, explains why this spring, chiffchaffs began to appear a few days earlier than usual. The British Trust for Ornithology’s reporting system, Birdtrack, showed clear signs of a mass arrival, with more reports of chiffchaffs than other traditionally early birds, such as the sand martin and wheatear.

By late March, chiffchaff was by far the most common singing bird on my daily morning bike ride, with roughly one a mile – a clear sign that this species, at least, is coping with rapid climate changebreakdown better than some.