Today I'm back to wing anatomy and the huge topic of coverts.
What are wing coverts?
As their name implies these feathers cover the important part of the wing - the flight feathers - and provide contouring so that air flows smoothly during flight.
There are coverts are on both sides of the wing: upperwing coverts and underwing coverts. Not only that, they are further divided and named by the part of the wing they cover.
Turkey vultures conveniently have darker underwing coverts than their flight feathers so I've marked the vulture pictured here to illustrate them. The primary underwing coverts are marked in blue, the secondary underwing coverts in pink.
If you look closely inside the blue square you'll see two layers of primary coverts which overlap like shingles on a roof. The top layer is called the greater primary coverts. The second layer, slightly lighter on this bird, is called the lesser primary coverts. If there are three layers the second one is called the median primary coverts and the third is called lesser. This three-tiered naming system applies to secondary coverts as well. On this bird it's hard to see if he has lesser secondary coverts. (Have these terms made you cross-eyed yet?)
Upperwing coverts are also named primary, secondary, greater, median and lesser. These coverts are the wing feathers you see when the bird is perched or standing. On many birds the upperwing coverts are colorful or striped and provide key clues to identifying the species. Take a look at warblers and you'll see what I mean.
So how many kinds of wing coverts are there? After tantalizing you with the topic I won't go into it very deeply but here's a list of as many wing covert names as I can find. Most of these come in upperwing and underwing varieties:
- Greater primary coverts
- Median primary coverts (I don't know of an example of these)
- Lesser primary coverts
- Greater secondary coverts
- Median secondary coverts
- Lesser secondary coverts
- Marginal coverts
- Alular quill coverts
Yow! This is almost boring. Fortunately there will not be a quiz.
(photo by Chuck Tague, altered to illustrate its underwing coverts)