One December, in midsummer South Africa, Tim Dee was watching swallows. They were at home there, but the same birds would soon begin journeying north to Europe, where their arrival marks the beginning of spring.

Greenery recounts how Tim Dee tries to follow the season and its migratory birds, making remarkable journeys in the Sahara, the Straits of Gibraltar, Sicily, Britain, and finally by the shores of the Arctic Ocean in northern Scandinavia. On each adventure, he is in step with the very best days of the year - the time of song and nests and eggs, of buds and blossoms and leafing.