Iridescence: Why a Ruby Throat Sometimes Looks Black

Posted by Vonda on Aug. 3, 2020

The male Ruby-throated Hummingbird is known for his brilliant red gorget. But sometimes, that gorget is less brilliant and more black than red, to the point that they could almost be mistaken for a Black-chinned Hummingbird if it were not for the range.

Male Ruby-throated Hummingbird with its striking red gorget

The red coloration is actually the result of iridescence rather than pigment in the feathers. The striking red color is produced by the reflection of light, and the intensity of the color will vary based on the direction the bird is facing and the amount of ambient light to reflect.

Male Ruby-throated Hummingbird, viewed from the side, appears to have a black throat

When viewed from the side, due to the angle of reflection, the throat appears darker, often black. All of the pictures in this post are of the same bird, taken only moments apart. In the above photo, the bird is in profile, and the throat appears black.

Ruby-throated Hummingbird showing a hint of dark red in the gorget

As the bird's angle shifts and he turns to start to face the camera, we can begin to see a hint of dark red as in the above photo. The more the bird spins to face the camera, the brighter the red gorget becomes as shown in the below photos.