At one time, the Blue-headed, Plumbeous, and Cassin’s Vireos were considered the same species called Solitary Vireo. Using genetic evidence the species were officially separated by the American Ornithological Union in 1997. While touring Aransas National Wildlife Refuge I was captivated by this vibrant Blue-headed Vireo (Vireo solitarius). I watched it hop around the live oak trees for a good twenty minutes. Mercifully, it halted for a brief respite so I could capture this image. Thank you, little one.