Monsal Dale, Derbyshire: Of the five common thrushes that call Britain home, these are the most unpredictable and least approachable

It was that dusk moment when the brown-green of the fields merged with the green-brown of the trees and Great Shacklow Wood ran a chromatic scale down its steep slope into gathering, unresolved darkness by the river; and over everything was palest ice-blue.

It was then that the redwings went to roost – a dozen silhouettes twisting and appearing almost to fall sideways with loss of control, as if anxiety were harassing them out of the sky. Then they entered the darkness and were gone. But what is it with redwings and those nerves?