fwd - Re: Reasons for feathers

[MKIRKALDY@aol.com]

Forwarded to the list for Pat Grant, who is not currently subscribed.

Mary
____

People have been talking about feathers for brooding and/or display, as
well as for insulation.  I don't know whether it counts as "display", but
there are several feather-related behaviours that could contribute to
survival.  For instance, some birds will fluff out their feathers when
threatened, sort of like a cat fluffing out its tail and fur.  (This may
apply especially to juvenile birds, I'm not sure.) This makes the bird
look much larger, and thus may give a predator pause, and also likely
makes it more difficult to judge where to grab or slash if one attempts to
seize the bird.  I particularly remember a picture of a young owl all
fluffed out, and boy did it look scary.

Another behaviour that might be relevant to the origins-of-feathers debate
--IF passerines are fairly basal, as I think has recently been
hypothesized--is juvenile feeding behaviour.  Young birds recently
out of the nest approach the parent, adopt a posture with the wings
partway open and flutter or vibrate them while screeching for food.
Romantically-inclined adult females may approach studly males and flutter
the same way.  In both cases, a more-impressive flutter tends to get a
more satisfying response.

There's also the flip side of display: feathers can be great camouflage.
They're especially great in that they can be cryptic on one side and
colourful on the other, or can be layered so that the display feathers
only show when the bird wants to show them.

No doubt some of the bird experts on the list could cite many other
examples of behaviour involving feathers that could contribute to survival
and/or reproductive success, some of which might have been contributing
factors in early feather evolution.

Pat