Systematics

Five subspecies are recognized (Paynter 1970, Dickinson 2003):

T. o. pusillus: Occurs from southeastern Mexico south to Colombia and northern Venezuela (Paynter 1970). Similar to intermedius, but "with the black markings in adult males still more extended, that beneath extending over breast, and in fully adult males the auricular region and crown black or mostly black" (Ridgway 1901: 534).

T. o. ravidus: Isla Coiba, Panama (Paynter 1970). Darker. In male, "black extends to nape, entire side of head, and to belly; green of upper surface darker;" in the female, "grayer green throughout" compared to pusillus (Wetmore et al. 1984).

T. o. olivaceus:  Cuba, Isle of Pines, Hispaniola, Jamaica, and the Cayman Islands (Paynter 1970).

T. o. intermedius: Occurs in Isla Cozumel, Mexico (Paynter 1970). Similar to nominate olivaceus, but "larger, the adult male with black on chest extending farther backward" (Ridgway 1901: 533).

T. o. bryanti: Occurs on Puerto Rico (Paynter 1970). Similar to nominate olivaceus, but "decidedly smaller, color much brighter olive-green above and the under parts more yellowish, the abdomen often light yellow (Ridgway 1901: 533).

The Yellow-faced Grassquit traditionally is classified as one of the five species of Tiaris. Phylogenetic analysis of DNA sequence data, however, reveals that Tiaris is polyphyletic (Burns et al. 2002, 2003). Tiaris (broadly) is embedded within a radiation that includes Loxigilla, Loxipasser, Euneornis, Melopyrrha, Melanospiza, and the geospizines (Darwin’s finches) (Burns et al. 2002, 2003). Tiaris olivaceus apparently is not the sister species to any other member of Tiaris, as currently constituted.