Hi all,
Kestrels are fantastic at hovering. I has seen them doing it in quite
strong wind, and almost still conditions. Te difference seems to be
that they are more "horizontal" in stronger breeze, and less so in
lighter breezes. Also, they probably do not hang stationary for as
long when the wind is lighter, but I have seen them hover for quite
some time even in still conditions - whether that constitutes a "true"
hover, I'll leave to those more expert in the field. Sadly, there are
VERY few Nankeen Kestrels in Tasmania, so it's not something I observe
as often as when I was growing up.
John Tongue,
Ulverstone, Tas.
On 16/07/2008, at 1:25 PM, Andrew Taylor wrote:
On Wed, Jul 16, 2008 at 12:35:58PM +1000, Chris Sanderson wrote:
I have observed Black-shouldered Kites, Nankeen Kestrels and Brown
Falcons
hovering on regular occasions. I understand Peregrine Falcons are
also
capable of the feat, though I have never seen them do it.
Evan is right. In most cases they would have maintaining a stationary
position with respect to the ground by flying into a headwind -
impressive
in itself but not strictly hovering. For most birds energy
requirements
are thought to follow have a U-shape with flight and very low speed
flight is either expensive or impossible. Despite kestrels'
adaption to
this hunting mode there are suggestions they are incapable of
hovering.
I don't know if this is correct - as a variety of birds seem capable
of
transient hovering - e.g I think I've seen spinebills, kingfishers,
tyrants and owls hover in still air - and of course hummingbirds.
Andrew
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