Vast flocks of female chaffinches are gone

‘The biggest flock of chaffinches I think I’ve ever seen consisted of at most 20 birds.’ Photograph: Ivor Toms/Alamy

In The Natural History of Selborne (1789), Gilbert White refers to flocks of almost entirely female chaffinches (Country diary, 23 January) appearing near the village around Christmas and is sufficiently intrigued to get friends and neighbours to confirm this. He seems to find the fact that these flocks are vast unremarkable. The biggest flock of chaffinches I think I’ve ever seen consisted of at most 20 birds. How depressing is that?
Rob Clack
Royston, Hertfordshire

• After Theresa May’s resignation, I attended a lecture given by Julia Gillard, the former Australian PM, and asked if she’d consider filling the vacancy. She replied with a very firm “no, thank you”. I imagine Jacinda Ardern would give the same answer (Letters, 24 January).
Anne Nelson
Oxford