Have you heard a Chiffchaff yet with its distinctive song? This amazing little bird weighing no more than 9 grams will have flown all the way from West Africa. As yet no one knows how long they take or what route as a satellite tracking device small enough has not yet been made. Unlike the cuckoo. The BTO (British Trust for Ornithology) has tagged several cuckoos and you can follow their progress by clicking here and going to the Cuckoo Tracking project.
If you found this interesting there will be lots more along similar lines in my book An Illustrated Country Year to be published later this year.