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.
The jangling keys song
The corn bunting’s song is one of the most distinctive sounds of lowland farmland — an accelerating rattle described variously as a bunch of keys, a jangling metallic chain, or the sound of breaking glass. Males sing persistently from prominent perches — fence posts, telephone wires, the tops of tall thistles — from March onwards, repeating the song throughout the day with mechanical regularity. The song carries considerable distances across flat farmland and is often the first indication of the bird’s presence.
Polygamy
Corn buntings have an unusual polygamous mating system in which successful males may mate with many females simultaneously. In high-density populations, dominant males have been recorded mating with up to 18 females in a single breeding season. The male has no role in incubation or chick-rearing — the female raises the brood entirely alone. Males spend their time defending territory and singing to attract additional mates.
Agricultural decline
Corn buntings have declined by over 90% in Britain since the 1970s — one of the sharpest declines of any farmland bird. The causes are well understood: intensification of arable farming has removed the winter stubbles (cut grain fields left through winter) that provided critical seed food, the rough grassland margins that harboured invertebrates, and the insect-rich summer foraging that fed growing chicks. The species is now largely restricted to eastern England in areas with sympathetic farm management.
Conservation measures
Agri-environment schemes that maintain unharvested winter cereal headlands, wide field margins, and grass buffer strips have shown benefits for corn bunting populations in targeted areas. The species responds well to sympathetic management but requires these measures at a landscape scale across multiple farms.