Thanks, Chris. I'll try to do that next time I see it. I'm glad you
cleared that up, or I would have made the same mistake with other birds.
Peter Shute
Chris Corben wrote on Thursday, 11 October 2007 2:15 AM:
> Birds without a trace of white at the edge of the tail often
> appear to have
> a contrasting white edge. This is because the outer web of
> the outermost
> tail feather can be exposed without any overlap by more inner
> feathers. The edge of each feather, by itself, can be quite
> translucent,
> and can let a lot
> of light through from behind, making it look pale. The rest
> of the tail
> feathers look a lot darker because they are overlapping each
> other, greatly
> reducing the transparency (and they may be more solidly
> formed, as well).
> Whether it is white or grey means nothing in this context -
> these are only
> relative degrees of darkness which only mean something in comparison
> to other nearby objects. Grey can look either white or black
> depending on what
> it is being compared to. The tail is quite dark overall, so
> if the outer
> edge is visible, it is likely to look a lot paler than the
> rest of the tail,
> and could therefore appear as white.
>
> The best way to determine the real colour of the outer tail feathers
> is to view them from below when the tail is closed right up. That
> way you see the
> undersurfaces of the outer rectrices against the dark
> background of the rest
> of the tail. It works for the same reason that a bird in
> general is much
> easier to see if it is against a dark background, rather than a pale
> background. You can see this easily by looking at a bird
> against the sky,
> when it will often look silhouetted and it can be very
> difficult to get a
> good appreciation of the colour. Often, all you have to do is
> move a little
> so the bird is visible against a dark background, such as the
> trunk of a
> distant tree, and you will see it much better.
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