Marshall (1992) Vireo gilvus V. de Santa Ana - In deep woods on gentle slope N base Cerro del Aguilá where undergrowth cleared for coffee planting & sunlight occurs on ground in large spots, there were a great many migrants, esp. vireos. Gilvus there every time I passed the area, not always singing, but could always turn up some by waiting long enough. Sometimes full song, sometimes scratchy whisper song; perched high above ground in crowns of green trees. Often 2 in a tree or vines. singing.