Thursday, September 6, 2012

Q&A Corner: West Nile Virus and Feathers

Q:  "I heard something about West Nile Virus making birds' feathers fall out - is this true?  Why does it happen?"

A:   Yes, it's true!

Here's something the average Human doesn't know about birds:  when our feathers are growing in, they're connected to an active blood source.  The blood provides the nutrients necessary to grow the feather, which is a much more complicated thing than a Human hair.  While these feathers are growing in, they're called "blood quills" or "blood feathers", and they look like this:
See the tube that looks kind of like a straw?  That's all full of blood as the feather grows.  When the feather is done growing, the blood source is cut off, and the feather looks like what you're used to.  Of course, while the feather is growing in, it's very important to not break it!  Thankfully, we birds have evolved a molting pattern than allows blood quills to grow in with the protection of other intact feathers around it, so it's not much of a problem in the wild. 
Broken blood quills from
 So, what does this have to do with West Nile Virus?  The virus often affects feather growth in birds, causing blood quills to pinch off and fall out prematurely.  Below on the left is a picture of what a feather looks like when it falls out normally during a molt, and on the right is what a pinched off blood quill looks like:

At the RMRP right now, the Humans are picking up a lot of feathers that look like the one on the right in the cages.  So far eight birds have been blood tested and confirmed for the Virus, but there are many more with West Nile Virus symptoms that are awaiting confirmation.  The good news is that most birds with WNV can be rehabilitated with supportive care and a lot of hard work from the Humans.  However, when birds have feather problems like those above, it can take many months of care for them to grow in normal feathers and be released.

Have more questions about WNV, or anything else for that matter?  Email me at and I'll do my best to answer your question!  You can also follow me on Twitter @RaptorProgram (I'm really very funny and interesting, I promise).  And, of course, there's the RMRP's Facebook page, which is pretty awesome, and the actual RMRP website at  See you around! 

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