Thanks. Yes probably connections there. Really though it is surely hard to
prove any of these things. I think that Superb Fairy-wrens wiggle the tail
is far more likely to be social signalling to others of their family group
to help them keep in contact. As for the White-faced Heron suggestion. I
think it is hard to see how that idea helps in feeding (how would it help to
disturb prey, which would presumably try even more to hide) other than to
assist visual perception. If they wanted to disturb prey you would think
they would not like to stand so still. Yes the head stays still but the
changing of the angle of view is sufficient to allow the two eyes to get a
moving focus from different directions and surely this helps in binocular
vision accurately assessing distance and exact pinpointing of the target.
With a small head, the distance between the two eyes is presumably not
enough to get sufficient binocular vision without the extra movement given
by that waggling. I easily agree with Graeme about the foot jiggling (though
I have seen this in water). Falcons and owls also may move their head around
when looking closely at something. This is surely to help seeing and judging
distance than disturbing prey.
Philip
-----Original Message-----
From: Birding-Aus On Behalf Of
Graeme Chapman
Sent: Wednesday, 4 May, 2016 4:41 PM
To:
Cc:
Subject: Red-capped Robin behaviour
Hello Sonja,
Feeding birds employ various methods to disturb prey or perhaps to improve
their vision when feeding. Your excellent pic suggests to me an adjunct to
feeding. The best example of this sort of thing that comes to mind is the
White-faced Heron - almost comical to watch - they waggle the neck to and
fro (the head stays still) and put one foot forward and jiggle it in the
grass to disturb prey. Superb Fairy-wrens wiggle the tail. Yellow-rumped
Thornbills flick the wings out quickly. Restless Flycatchers spray the
ground with their scissors-grinding call. and so on
Cheers
Graeme
<HR>
<BR> Birding-Aus mailing list
<BR>
<BR> To change settings or unsubscribe visit:
<BR> http://birding-aus.org/mailman/listinfo/birding-aus_birding-aus.org
</HR>
|
