Northern rough-winged swallow - what's with the "rough wing"?

A small gathering of rough-winged swallows near a pond in Kelowna.

Thanks to a number of helpful bird enthusiasts, I determined yesterday that my unknown flycatcher was actually a type of swallow I had never seen before.  After learning the name, I had to do some research on what the moniker "rough wing" was about.  I know that owls have frilled/soft-edged feathers to allow them to fly silently, so what is going on with this bird's so-called "rough" wings?

You can see in the above image that the leading edge of the swallow's primary feathers has a series of hooks or barbs.  This gives the wing the rough feeling that you get when you run your finger across its edge.  This is unlike normal feathers that are smooth all the way along.

The fact is that the purpose of these barbs is as of yet unknown.  There is some speculation that it may affect the sound of the bird's flight and may be involved in mating.  Given the dull appearance of the creature, I could see that it may use the sound as a way of either calling to a mate or defending its territory.  That, too, of course, is speculation.

I did find one interesting note on the subject though.  Apparently, Russian explorers used the bird's wing to comb their rather bushy eyebrows.  I'm glad they didn't name the bird after that - can you imagine?  "Look, Molly, it's the Russian-eyebrow brush swallow!"  

For an interesting (and humorous) read on the subject, click here.

Thanks for reading.

Eric Svendsen     www.ericspix.com