Green’s Dictionary of Slang

1. a male singer.

1728		J. Dalton Narrative of Street-Robberies 41: One of their Songs, which is sung at the Club by that charming Warbler, Miss Irons [a homosexual].
1756		Sussex Advertiser 22 Nov. 2/2: This Day is publish’d [...] The Warbler, or Songsters’ Delight [...] recommended to all Lovers of Vocal Musick.
1860		R. Nicholson Rogue’s Progress (1966) 26: A teacher of music [...] Mr Wood [...] the sweetest singer I ever heard as a ‘warbler’.
1861		Dundee Advertiser 17 July 4/6: And the warbler is dead! Great Amodio is dead and buried.
1885		Bulletin (Sydney) 10 Jan. 5/3: And we can tell you, too, about a catholic concert at Adelong, at which [...] an Andalusian warbler (named Lonergan) gave ‘Pom Pom’ with much effect.
1900		Bulletin (Sydney) 1 Dec. 12/3: The average operatic tenor is a modest daisy, and Louis Arens, one of Musgrove’s chief warblers, has been at some expense and trouble to prove it.
1902		‘Billy Burgundy’ Toothsome Tales Told in Sl. 54: The heavy-hearted black warbler flashed a clipping.
1907		N.Z. Truth 21 Dec. 7/3: That jolly German warbler burst out laughing.
1910		Sun. Times (Perth) 17 July 2nd sect.9/1: They Say [...] That the male warbler, especially barred. by the absent boss, was there nightly singing soulful ditties.
1929		W. Winchell On Broadway 6 July [synd. col.] Irving M. Ureles, an obscure warbler, who was given a tryout last week.
1952		(con. 1920s) G. Fowler Schnozzola 49: Two pals, Eddie Jackson and another warbler, Lovesong Harris, chipped in from their tips.
1983		J. Byrell (con. 1959) Up the Cross 137: [P]laying some Sinatra and Ella records [...] since they happened to be Kev the Kidder’s all-time top warblers.

2. ‘Warblers, singers who go about to “free and easy” meetings, to chaunt for pay, for grog, or for the purpose of putting off benefit-tickets’ (Jon Bee).

1823

‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc.

3. a female singer.

1809		B.H. Malkin (trans.) Adventures of Gil Blas (1822) II 228: I [...] learned, a very short time after, that he had got into the trammels of a little warbler.
1860		Western Times 29 Sept. 6/1: To Madame Clara Novello on her intended Retirement. Enchanting warbler! [...] our ‘Queen of Song’.
1889		Liverpool Echo 3 June 4/5: The Warbler’s Return. Madame Albani reappeared at the Royal Italian Opera [...] in ‘La Traviata’.
1904		Sun. Times (Perth) 10 Jan. 4/8: [headline; ref. to singer Ada Crossley] A Weepful Warbler.
1915		S. Ford Torchy, Private Sec. 277: That blue-eyed warbler you used to be so nutty over.
1929		C. Coe Hooch! 193: She’s a warbler over in a night club.
1938		J. Weidman I Can Get It For You Wholesale 227: Martha Mills, the baby-voiced warbler of Smile Out Loud.
1941		D. Burley N.Y. Amsterdam Star-News 24 May 13: Helena [Horne] , admittedly the most sought-after warbler of the day in chirpville.
1952		W. Winchell ‘On Broadway’ 22 Sept. [synd. col.] Garry Moore and his wife are unhitching [...] Denise Lor (warbler on his show) is his next.
1983		J. Byrell (con. 1959) Up the Cross 104: Gloria [...] was a nightclub hoofer and warbler.

4. (US Und.) a public defender.

1950

Goldin et al. DAUL 234/2: Warbler. (Chiefly in the Prairie States) A criminal lawyer.