Related Clues:

• Rapid alternation of notes
• Twitter? It's despicable by the sound of it
• Play casually on the river Lune's banks
• Young bird's chirp
• Warble the opening of 'Traviata' badly
• Birdsong excited emotion? Not hard
• What a warbler might do in source of trout stream?
• Whistle that is nominally shared by two quarrelling brothers
• Sound bringing tingle, hard to miss
• Skylark sound
• Young bird's cry
• Sound like a bird
• Sound from a hen's brood
• Warbling sound made by a songbird
• Reportedly vulgar tweet