Clauson (1972)
An etimological dictionary of pre-thirteenth-century Turkish
p. 9
üpgük
the earliest of several early onomatopoeic names for this bird; the others are assembled below; some s.i.s.m.l., occasionally with the extended meaning in Çağ. Türkü viii ff. kara: üpgü:k ‘the black hoopoe’ IrkB 21: Uyğ. viii ff. Civ. üpüp kuşnuŋ sügükin ‘the bones of a hoopoe’ TT VII 23, 5: Xak. xi üpüp al-hudhud ‘hoopoe’; dialect form of (luğa fi) üpgük Kaş. I 78; Çiğil xi üpgük al-hudhud Kaş. I 110: xiv Muh. hudhud übü:k (not vocalized) Mel. 73, 4 (v.l. ibi:k); Rif. 176: Çağ. xv ff. übük ‘the crest’ (tâc) on the heads of such birds as the cock and the hoopoe (hudhud), and metaph. ‘hoopoe’; the latter is also called püpük and püpüş and, in Rûmi, ibik; übük kuşı ‘hoopoe’ in Pe. şânasar San. 58v. 2: Kip. xv hudhud übük Tuh. 37b. 10: Osm. xv ff. ibik/ibük c.i.a.p. TTS II 511; III 351; IV 405.