About us: We own the Wild Birds Unlimited nature shop in East Lansing, Michigan,
a store that provides a wide variety of supplies to help you enjoy the birdwatching hobby.

This blog was created to answer frequently asked questions & to share nature stories and photographs.
To contribute, email me at bloubird@gmail.com.

Monday, August 17, 2015

Hummingbird with a black throat

My dad called out excitedly the other day that there was a black-throated hummingbird at the feeder. As we made a closer inspection, the black turned a brilliant ruby color when the sun hit his neck. The patch of colored feathers found on the throat of many male hummingbirds is called a gorget. The term is derived from the gorget used in military armor to protect the throat.

When the sun hits the feathers on an adult ruby-throats’ gorget they appear brilliant red. Then when he shifts his head a little the gorget can appear black. That’s because the iridescent feathers on the throat lack true pigmentation. The ruby red color our eyes see is actually the product of the feathers’ structure.

The iridescence is caused by refracting light waves off minute air sacs or platelets in the feathers, sort of like when light hits a soap bubble. The different colors produced are often a result of pigmented melanin within the platelet.
Possible functions for the flashy feathers may be to attract a mate, signal social status among males or communicate a threat. Young hummingbirds, which need to intrude on adult territories to feed once they have fledged, all lack gorgets. This may help to make them less visible or less threatening to adult birds.

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