Corn Bunting
The largest British bunting — a large, streaky, plain-brown bird of arable fields with no distinctive markings but an utterly unmistakable song, often described as jangling keys; the corn bunting has declined severely across Britain as intensive farming reduced the cereal stubble, rough grassland, and insect-rich field margins on which it depends; polygamous males may mate with up to 18 females in a season.