Take a walk through a weedy meadow or shrub-filled forest edge and there’s a chance you might spot a flash of brilliant jewel blue singing boisterously from a treetop or telephone wire.

Not only are male Indigo Buntings gorgeous in their azure plumage, but they are also prolific singers and may whistle their high-pitched songs from dawn until dusk. Individual notes are often clustered in pairs and pairs often come in threes (“what what, where where, here here?“) but songs can vary widely from one individual to the next—young males learn their songs not from their fathers but from their nest neighbors, creating distinct “song neighborhoods”.

Fascinatingly, Indigo Bunting feathers contain no blue pigment. Like all blue birds, their coloring comes from the microscopic structure of the feathers that refracts and reflects blue light and absorbs other colors. Females are plain brown but may occasionally have a slight hint of blue on their wings, while immature and molting males have splotchy blue and brown patches.

Here are five photos of male Indigo Buntings from our annual Picture This: Your Great Outdoors photo contest. The 2019 contest is open, so submit your nature photography today!