The Black-whiskered Vireo’s “whiskers” are in fact thin black stripes along the sides of its throat, a feature that distinguishes it from the very similar Red-eyed Vireo. Black-whiskered Vireos are a summer breeding resident of mangrove and tropical hardwood forest; the best time of year to search for them is when males are establishing their territories between April and June. They favor nesting in red mangroves, where it selects a fork of a slender limb about 6 feet off the ground or water and builds a deep basketlike cup lined with lichen, plant fibers and spider webs.