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Thread subject: Hovering Technique of Ospreys.
Name Date Message
Marie 09/06/05 06:24 pm Having watched the hovering technique of the osprey yesterday a number of times and marvelled at its prowess I thought I would share some of these gems of wisdom from my Bird Migration book by, Thomas Alerstam. Swedish Author.
In it he says that ospreys are powerful and tenacious fliers, which is clearly demonstrated by their hovering technique over water to locate a fish below. They usually do this before they fold their wings to commence their dive. This flight technique is very wasteful in terms of energy apparently. (Still, from my opinion it works and looks most graceful osprey and the kingfisher seem to share this behaviour for fishing) I am sure I witnessed this behaviour of hovering by one of the Willows beach eagles last year when attempting to catch a sea duck. they didn't catch it because they got exhausted by this behaviour.
So it goes on to say, on migration though, the osprey soars and glides to a lesser extent than other birds of prey, and it flies long distances over the open sea and desert as we well know.
But did you know that Ospreys with Gannets and Terns have continuous molts, because of the need to have perfect flying ability for fishing and twice yearly migration.The individual primaries are shed sequentially from the inner to the outer one. This way the tip of the wing is the last feather to be replaced. Not until a new primary feather is almost completely grown does another one next to it start to be replaced. The inner feathers can be replaced almost four times, as in the case of Ospreys, before the last primary at the tip of the wing gets replaced. Apparently any wing feather is used by an osprey for 1.5 yrs before being exchanged for a new one. Since the nature of the molt takes place symmetrically on both wings, Ospreys are always able to perform their migration and hovering abilities without any need for Time-out!
Celeste 09/06/05 06:36 pm Lots of new info....thanks Marie!
cathy 09/07/05 08:18 am Ospreys are wonderfully designed. The Boeing V-22 Osprey takes its inspiration from natural Ospreys - having propellers that move the plane forward and then rotate to be helicopter rotors so it can hover. It has some problems, however. So maybe molting is the next thing it should do.
Melanie 09/07/05 10:44 am Unfortunately, those in the military have no-so-very affectionatley nicknamed V-22's "Lawn Darts". The American military has as much trouble flying those as we do another aircraft named for another raptor, Harriers
cathy 09/07/05 10:53 pm Maybe mimicing natural ospreys, they should be used for "fishing airplanes" - why dive to earth and be a lawndart?

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