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.

Wednesday, April 25, 2012

Why the color on a hummingbirds’ throat flashes

As the hummingbirds begin to visit our feeders more frequently you may notice the bright colors that flash on the male Ruby-throated hummingbirds’ 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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2 comments:

Mary Pellerito said...

I love your blog and send out posts on twitter and facebook. I try to support Michigan businesses. What kind of trees/shrubs do hummingbirds nest in here in Michigan? I want to make sure I have food and a place for them to live when they visit.

Wild Birds Unlimited Mid-Michigan said...

There is no particular tree species in which hummingbirds prefer to nest. They first look for a territory that supplies enough bugs and nectar to support them and their babies. Next they look for a tree that provides proper camouflage and protection from predators.

An attractive nesting tree will have some pencil thin flexible branches that slope downward slightly. The tiny golf ball sized nest, constructed below a leaf canopy and above a fairly open area, starts with spider silk to attach the nest and make it flexible. Lichens camouflage the outside, and the inside is lined with cotton from nesting material, dandelion, cattail, or thistle down.

If a Ruby-throat nests near your feeder she may appreciate quick bites to eat while incubating eggs. When the chicks hatch, they need lots of protein, so their mother spends a lot time foraging for small insects and spiders. Throwing old banana peels in the garden as compost will attract fruit flies for the hummingbirds and fertilize your garden.

After the chicks leave the nest, mommas will bring these newly fledged hummers to feeders and you can watch them check out everything to see if it is food. It usually takes them awhile to figure out, so fledglings are fed by their mother for another 10 days.

Young hummingbirds will look similar to a female, but as young males begin to mature in late summer look for a few random red iridescent feathers on the throat. And the young are very healthy looking. Their feathers are full and shiny whereas the parent birds look a little haggard. It is thought that Ruby-throats live as long as 12 years, but the average is probably 3-5 years.

If you keep your feeders filled and fresh you should have hummers visiting from April until usually the end of October.