Philadelphia (Vireo philadelphicus), left from Costa Rica 2/05 and Warbling from Iowa 6/05. Philadelphia Vireo (Vireo has a broad white crescent under the eye to counter-balance the white above the eye. Warbling Vireo is similar, but lacks the yellow on the throat and mid-breast and the lores are paler, giving it more of a "blank-faced" look. Philadelphia Vireo has a yellow throat and breast, with the brightest yellow in the middle of the breast. Even a drab Philadelphia should show some yellow in the throat. A fairy heavy dark lore also favors Philadelphia.