There is a plain bird, perhaps the plainest, a tiny thumb-sized bird with grey above and dusty white below. You most likely have never seen the Warbling Vireo but you for sure have heard this day time singer. The vireos are warbler like in size, migratory, insectivores that grab caterpillars from the leaves and flies from the air. They are non-descript in looks and non-descript in behavior, lurking high up in deciduous trees like oaks and maples. But vireos make themselves known by their loud, repetitive song. Unlike a chickadee for example, that has specific phrases to its song like the namesake “chick-a-dee-dee-dee” vireos are more improvisational giving a series of evenly spaced though varying phrases. The Red-eyed vireo’s song is often described as the phrases “here I am, where are you? Pick it up, put it down. Over here, over there” and on and on. The spacing and tempo of these phrases is a crucial tool for field identification. Of the three vireos we are most likely to find this time of year we can separate them out using the spacing of phrases. The Blue-headed vireo’s song is bury and husky, and slowly delivered. With a slightly faster delivery and a far greater stamina, the Red-eyed vireo’s song is often song throughout the day from a high vantage point, and sung with long determination. Finally, the Warbling Vireo who’s song has no breaks in it at all, but instead is a kind of rush of sound, the way a child might taunt a slower child into a chase on the playground, “nana nana na-na-na”. Learning to hear these subtle differences will unlock some new, hard to spot species singing over your head all summer long.