Vireos (Vireonidae)

Yellow-green Vireo (Vireo flavoviridis) - HBW 15, p. 431

French: Viréo jaune-verdâtre German: Zitronenflankenvireo Spanish: Vireo Verdiamarillo

Taxonomy: Vireosylva flavoviridis Cassin, 1851, San Juan de Nicaragua, Nicaragua.
Probably forms a superspecies with V. olivaceus, V. gracilirostris, V. altiloquus and V. magister. Frequently treated as conspecific with first of those, but differs morphologically and vocally, and biochemical studies indicate that the two diverged from each other c. 4-6 million years ago. Proposed race insulanus, described from I del Rey, in Pearl Is (Gulf of Panama), is synonymized with nominate. Three subspecies recognized.

Subspecies and Distribution:

flavoviridis ( Cassin, 1851) - breeds Rio Grande delta (S USA-NE Mexico border) and S in Mexico (from NC Sonora in W and from N Tamaulipas in E) through Central America to C Panama (including Coiba I and Pearl Is), possibly also to E Panama (Darién) and adjacent Colombia; migrates to NW South America (Colombia S to Bolivia).
forreri Madarász, 1885 - breeds Tres Marias Is, off Nayarit, in W Mexico; migrates to Amazonia.
perplexus ( A. R. Phillips, 1991) - breeds N Guatemala (Petén), possibly also adjacent SE Mexico; migrates to E Ecuador and E Peru.