Brown booby fishing - what's wrong with this picture?

Brown booby flying with its head twisted sideways, looking for fish.

OK, this one was weird.  We are cruising along on our ship, and I am on the Promenade with my camera and long lens, photographing the various boobies that are searching for fish.  You can't actually see what they are doing very well, even with a good telephoto; the most you can usually do when the birds are flying is to try to keep them in the viewfinder and maintain a focus lock.  It's not until you get the photos back to your computer that you can really review them well.

And then I see it.  This booby, with its head rotated 90°, is flying along, looking straight down.  Not with both eyes, with one.  Now, many birds have lousy binocular vision to begin with, as their eyes are at the sides of their heads instead of in front, like owls.  And flying horizontally with your head facing down is not very aerodynamic.  So, this bird seems to have found a solution to that problem.  Keep your head and bill straight to reduce drag, rotate your head sideways so one eye points straight down to use the best vision to search for fish, and fly along as normal.  When a fish appears, rotate everything into plunge mode and dive.  Now use both eyes to help estimate distance to water and fish.

I took dozens of photos, and this was the only one like this.  Was it a one-off, just a single bird that learned to hunt more efficiently?  Did it maintain this pose for a while or hold it a long time?  Did other boobies do the same thing, and I never caught it because it only rarely happens, and then just for a moment?  

It turns out that brown boobies have eyes that are relatively fixed in place, so turning their head sideways is a good way to see what's beneath them.  Plus, they shift their heads constantly in order to form a picture of where they are.  I guess I just caught this one in mid pose.  Lucky capture.

Thanks for reading.

Eric Svendsen     www.ericspix.com