CEO of the British Trust for Ornithology Juliet Vickery is particularly fond of brent geese, having studied them on the Norfolk coast for three winters. They are our smallest goose, which migrate from the Arctic Circle every year. She describes what she learnt about fluctuations in their population, and the fascinating connection with lemmings in the Siberian tundra.

Produced by Sophie Anton for BBC Audio in Bristol.

This programme features recordings from Xeno-Canto by David Darrell-Lambert (XC994302 and XC994306)