warble · verb, noun1
Perhaps onomatopoeic.
warble · noun2
- Frankish · derived from*werbel
- Middle English · inherited fromwerble
- English todaywarble
From Middle English werble (at least for the noun), from Frankish *werbel (mole cricket), cognate to Walloon waerbea.
Etymology from Wiktionary, CC BY-SA 4.0.