Hi all,
Thought I'd get a response on fantail foraging from someone who I knew had
done some looking into the topic before. Here's what Ricki had to say.
Regards,
Chris
---------- Forwarded message ----------
From: Ricki Coughlan <>
Date: Aug 20, 2006 8:16 PM
Subject: Fantail foraging
To: Chris Sanderson <>
G'day Bird lovers
Generalising is seldom a good idea when it comes to a class which has the
massive variation of the birds, though we all fall into the trap of doing so
now and again. I think, Phillip, that it might be your turn to do so here
with regards to tail fanning. You may well be right about a number of
species and possibly the Whipbird but almost certainly wrong about fantails
for the most part. Firstly though, as an enthusiastic insect photographer, I
cannot possibly count how many times moving shadows have startled insects,
causing them to fly, jump or run away. That it is not the movement of a
nearby object is clear, as long morning and afternoon shadows from objects
moving in the distance have frequently been my nemesis.
There is a good body of evidence to support the theory that Willie Wagtails
not only employ their tail feathers as a means of startling their prey, but
they also use the shadow which is cast by their tails to flush insect prey
off the ground ahead of them. Personally, for many years when running around
Sydney's Centennial Park and Scarborough Park in the early morning or late
afternoons I had observed Willie Wagtails following the leading edge of my
long shadow as I crossed grassy areas. It was clear that the wagtails were
taking insects which were startled and flushed by the movement of my passing
shadow and I would often end up with several in tow. I have also observed
Willie Wagtails following the shadow of my car in parking lots and taking
invertebrate prey which that shadow flushed, some metres from my passing
car.
When preparing an assignment on the Foraging Behaviour of the Willie Wagtail
for university all of my observations revealed that Willie Wagtails indeed
use wing flashing and tail fanning as a means of flushing prey, they also
employ the shadows of their wings and tails in this process. Indeed, Willie
Wagtails mostly employ those tactics in situations where a strong shadow
will be cast, otherwise they prefer the "dash and grab" technique or employ
aerial foraging. I spent weeks quantifying their foraging activities and
then entered the results into a frequency table. The results were
remarkable. But don't take my word for it, have a look at the work of
Elizabeth Cameron in the chapter "Habitat Usage and Foraging Behaviour of
Three Fantails" in "Birds of Eucalypt Forests and Woodlands" published by
Birds Australia. Also, look at the work of Webb-Pulman and Elgar in "The
influence of time of day and environmental conditions on the foraging
behaviours of Willie Wagtails". This second work, published in the
Australian Journal of Zoology Volume 46, totally supports my findings.
I can't recall observing Northern Fantails using their tails at all in
foraging (which is not to say that they don't), however I have frequently
observed Mangrove Grey Fantails, Grey Fantails and Rufous Fantails using
their tails as a flushing tool. I've not noticed them ever using the shadow
cast by their tails specifically. However, I cannot recall a time when I
have seen these birds fan their tails when not foraging and that's pretty
telling. Fascinating genus.
Happy birding
Ricki Coughlan
Bird surveys, walks & talks
Phone: 02 9453 2274
Mobile: 0400 436 910
www.rickicoughlan.com <http://www.rickicoughlan.com/birdnote>
In a world older and more complete than ours they move finished and
complete, gifted with extensions of the senses we have lost or never
attained, living by voices
we shall never hear. They are not brethren, they are not underlings; they
are other
nations, caught with ourselves in the net of life and time, fellow prisoners
of the
splendour and travail of the earth."
- Henry Beston
===============================
www.birding-aus.org
birding-aus.blogspot.com
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
===============================
|
