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I think this stuff is well known. I thought I
recalled Joe Forshaw describing cockatoos as left-footed and parrots as
right-footed but apparently it is not that simple. See his 1981 book Parrots
of the World, second, revised edition, page 31. See also Prendergast,
H.D.V. (1985), 'Gang-gangs: left-footed all?' Canberra Bird Notes
10: 91-92 (The cover picture of CBN (by W.T. Cooper and now COG's
emblem, is relevant!) and Watts, B.T. (1986), 'Letter to the editor',
Canberra Bird Notes 11: 19. This describes Gang-gang Cockatoos
as left-footed and Purple Swamphen as right-footed. I'm sure I have read several
other short articles on this issue. As to why, well that seems fairly simple.
Somewhere in their evolutionary past, the stock species (plural), as a random
event, developed tendencies for one or the other and derived species maintained
that trait. There is no need to invoke any suggestions of adaptive advantage
towards favouring one foot or the other. There is however a definite advantage
of not using both feet in this manner, otherwise the bird would fall
over.
Philip
-----Original Message-----
From:
Lynda Chambers <>
To: Jack
Shapiro <>
Cc:
<>
Date:
Friday, 28 July 2000 8:40
Subject: [BIRDING-AUS] Re:
Footedness in Parrots
Jack,
Lesley Rogers has
also asked the question "Why are
some species left-footed and others
right footed?".
She gives two possibilities. First, that it
may be
dependent on the "particular direction of laterality
in
the perceptual processes used in feeding behaviour
in the given species
or, indeed, in the given individual".
The alternative is that it
depends on the type of
searching strategy that the species uses in
feeding.
Rogers suggests that "left-footedness may occur
in
species in which foraging involves greater use of
spatial cues
rather than detailed discrimination
of food objects from the background,
and vice-versa
for right-footed species". She concludes
however that
much more data is need on Austrlalian species.
The
aims of my (Victorian Ornithological Reseach
Group) study is to collect
additional observations
on a wide variety of Austrlalian parrot species
with
one of the aims to determine if there are differences
in
handedness on the individual and species level and,
if so is it related
to foraging methods.
References to Roger's work
include:
Rogers, L.J. 1980. Lateralisation in the avian
brain.
Bird Behaviour 2:1-12
Rogers, L.J. 1981. Environmental
influences on brain
and lateralization. The Behavioral and Brain
Sciences
4:35-36
Rogers, L.J. 1989. Laterality in Animals. The
International
Journal of Comparative Psychology 3(1):5-25.
As
collection of data on handedness in parrots is largely
opportunistic we
certainly welcome additional observations
from interested
persons.
When observing the birds using their feet to
manipulate
items it is useful to record the following
information:
Date, Location, Species, wild/captive, foot used,
surface
(eg ground, perch), object (eg seed pod, stick)
regards
Lynda
Chambers
Bureau of Meteorology Research Centre
Street Address: 150
Lonsdale Street MELBOURNE Vic 3001
Postal Address: GPO
1289k MELBOURNE Vic 3001
E-Mail:
Phone :
+613 9669 4784 Fax : +613 9669 4660
WWW Page: http://www.bom.gov.au/bmrc/mrlr/lec/lec.htm
(to
get to the Handedness in Parrots study follow the
links "Victorian
Ornithological Research Group" then
"Handedness in
Parrots")
On Thu, 27 Jul 2000, Jack Shapiro wrote:
>
27/7/00
>
> Hi Lynda,
>
> According to a message
attached below, in which you "welcome more
> observations on the
subject" of footedness in cockatoos you may be able to
> provide
an answer a question of interest to me.
>
> Do you have any
idea of your own, or from reading the literature as to why
> most (all
?) cockatoos and many parrots are left footed and others are not ?
>
> Your comments would be appreciated.
>
> Jack
Shapiro
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