The headword, a masculine noun in the nominative singular, is attested only here and at Theognostus, Canones 384.6. The latter passage identifies it as a proper name, with omicron as the first vowel. However, this appears to be a lexicographical error, as *flw=ros with an omega is a widely attested proper name. The Suda appears to be correct: spelled with an omicron (not omega as in the scholia to Oppian, Halieutica 1.157), this is the name of an Old World bird; see n. 1 below.
[1] Probably the Bee-Eater (Merops apiaster; Peterson, p. 140) or the Golden Oriole (Oriolus oriolus; ibid., p. 189), both of which are summer visitors to Europe; see LSJ s.v.
[2] The proper name is similarly glossed by ps.-Zonaras 1813.20 (Tittmann) and ps.-Herodian, Partitiones 146. Adler also cites the Ambrosian Lexicon (356). One prominent Phloros was an aristocrat and senator in Constantinople who became a monk and founded a monastery (cf. iota 447 end) after his family died during a pestilence (late C6 CE); Hatlie, p. 187.