Evidence suggests songbirds can also learn variations in songs from one another and that these changes last across generations: One 2016 study found variations in yellowhammer bird songs were preserved for up to 100 years.

"He knew the hardship of farmers in the 1920s and 30s but he knew it was also incredibly beautiful; there was an amazing wild profusion of yellowhammers, nightingales, linnets, that are a rare sight today."

On a recent visit, half a dozen yellowhammers busied themselves atop a high bush.

At last he saw the first of the dawn, like light faintly perceived round a corner at the far end of an unknown burrow; and in the same moment a yellowhammer sang.

He was speaking quietly, because he'd just heard the song of a yellowhammer bird that was hiding in a nearby patch of gorse -- a few short notes followed by a longer one.