I do not believe that thermaling birds, including the Redtail Hawk has
a preference of direction to cicle in a thermal. One reason that I think
this is the fact that I have observed what is referred to as 'kettles',
large groups of 50 or more hawks in a thermal, usually during the fall
migration.
If what you say was true, most if not all, these birds would be cicling
in the same direction. They do not. Many birds, in the same thermal,
will be circling in both directions.
I do know an 'expert' birder named Scott Weidensal??(spelling) who has
written many books about hawks and migrating birds, and I will
definately try to run this past him.
Also I will be making a greater effort in the future, when watching
vultures and hawks thermal, to pay very close attention to which
direction they are thermaling.
Daniel Boyer wrote:
> No, not all birds obey this "rule of thumb" all the time, but we are trying
> to look at the big picture, not exception... I am sure the Turkey Vultures
> have a reason for not always turning left...maybe because their wings allow
> them to do right turns in a left turning thermal, but "most birds will turn
> counter-clockwise, in the Northern Hemisphere, with the thermal" (a quote
> from a handout that was a page copied from a textbook, which was handed out
> during one of the lectures that I sat in on this past semester.) I'm not
> saying I'm an expert (I'm a molecular biologist), just restating what I was
> told by people that I consider experts... (I do know that all the red tailed
> hawks I have watched, over the past year, always thermal turn to the
> left...JME)
>
> Daniel
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