buntingyoudaoicibaDictYouDict[bunting 词源字典]
bunting: Bunting ‘bird’ [13] and bunting ‘flags’ [18] are presumably two distinct words, although in neither case do we really know where they come from. There was a now obsolete English adjective bunting, first recorded in the 16th century, which meant ‘plump, rounded, short and thick’ (could a subliminal memory of it have been in Frank Richards’s mind when he named Billy Bunter?).

Perhaps the small plump bird, the bunting, was called after this. The adjective probably came from an obsolete verb bunt, which meant (of a sail) ‘swell, billow’, but since we do not know where that came from, it does not get us very much further. As for bunting ‘flags’, the word originally referred to a loosely woven fabric from which they were made, and it has been conjectured that it came from the English dialect verb bunt ‘sift’, such cloth having perhaps once been used for sifting flour.

[bunting etymology, bunting origin, 英语词源]
bunting (n.1)youdaoicibaDictYouDict
"flag material," 1742, perhaps from Middle English bonting gerundive of bonten "to sift," because cloth was used for sifting grain, via Old French, from Vulgar Latin *bonitare "to make good."
bunting (n.2)youdaoicibaDictYouDict
lark-like bird, c. 1300, bountyng, of unknown origin. Perhaps from buntin "plump" (compare baby bunting, also Scots buntin "short and thick;" Welsh bontin "rump," and bontinog "big-assed"), or a double diminutive of French bon. Or it might be named in reference to speckled plumage and be from an unrecorded Old English word akin to German bunt "speckled," Dutch bont.