..... and the good old "A New Dictionary of Birds" - this is
the 1964 edition
edited by Landsborough Thompson , section author James Harrison
states:
Leucism (paleness) is closely allied to albinism and results from
varying
degrees of dilution of normal pigmentation .... it is often possible to
grade
the cases from a rufous leucism to a pale ginger and then on to
silver-grey and
on to an almost or even absolutely total albino.
Xanthochroism, the occurrence of yellow colour variants, is less usual
although
the 'lutino' varieties of some of the Psittacidae are well known .... as
well as
the very numerous varies of the Canary.
Pete
At 10:00 AM 2/06/2004 +1000, you wrote:
Hi
Philip and others,
My understanding is that while
a lutino bird displays an excess of yellow a leucistic bird is deficient
in melanin in some or all feather tracts. For example I found this on the
web...
Buckley, P. A. 1982. Avian genetics. Pp. 21-110 in M. Petrak (ed.),
Diseases of cage and aviary birds, 2nd ed. Lea and Febiger,
Philadelphia. "Perhaps more loosely and improperly used than any
other term relating to color in birds, albinism is, no more and no less,
the complete absence of all pigmentation, resulting in white feathers
(for the reasons just discussed), pink eyes (no melanin obscures blood
circulation, cause of the pink color) and light bills and legs/feet.
Albinism is all or nothing, and a bird can no more be a 'partial albino'
than a female mammal 'partially pregnant.' ... What is most frequently
termed albinism by the layman is properly called leucism. It may be
complete or partial, bilaterally symmetrical or asymmetrical, and may
affect melanins, carotenoids and porphyrins differentially. Leucism is
simply the complete loss of a particular pigment, or all pigments, in
feathers but not in soft parts. It may be as slight as a single white
primary feather on only one wing, or as pervasive as an all-white bird
with normal eyes, bill and legs" (p. 65).
In birding circles it seems to
have been commonly used in this way for at least the last 20
years.
Regards
Rohan
- -----Original Message-----
- From:
Behalf Of Philip A. Veerman
- Sent: Tuesday, 1 June 2004 5:27 PM
- To:
- Cc: birding aus
- Subject: [BIRDING-AUS] Mystery bird at Pt Cook
- By the description, I don't know that it is leucism. It seems to be
melanin deficient, rather than yellow excess.
-
- Philip
-
- -----Original Message-----
- From:
<>
- To: Carol Probets
<>
- Cc:
<>
- Date: Tuesday, 1 June 2004 16:56
- Subject: RE: [BIRDING-AUS] Mystery bird at Pt Cook
- What causes ?leucism? in birds?
- There was a leucistic Superb Fairy Wren at the You Yangs in Victoria
last year (possibly still there). It was a really amazing bird to
see, and almost seemed like a new species.
- The You Yangs is only 50km from Point Cook, so would environmental
factors play a part in the development of this syndrome?
- Peter
- Carol Probets <>
- Sent by:
- 01/06/2004 04:45 PM
- To
- cc
- Subject
- RE: [BIRDING-AUS] Mystery bird at Pt Cook
- Almost 20 years ago I was regularly seeing a leucistic New Holland
- Honeyeater in heathland at Mt Victoria (in the Upper Blue Mountains,
- NSW). This bird was bright white all over, except for the normal
- yellow on the wings and tail, and a faint smudge of grey around the
- face where it's usually black. With this colour scheme the bird
- almost glowed. It seemed to interact normally with the other New
- Hollands. I still have a couple of slides of the bird which were
- taken by a friend.
- As chance would have it, a couple of years later I saw another
- similar bird at Katoomba (which is 15km from Mt Vic).
- Cheers
- Carol
- Carol Probets
- Blue Mountains NSW
- 100km west of Sydney
- Rohan Clarke wrote:
- >It is almost certainly a leucistic New Holland Honeyeater that I
- >found and photographed near the last carpark at the beach BBQ
area
- >last week. It has a black head and yellow patches in the wing and
- >tail but the rest of the bird's plumage is cream. When I get
around
- >to converting the images from raw format to jpg I'll send you
some
- >record shots.
- >Regards
- >Rohan
- --------------------------------------------
- Birding-Aus is now on the Web at
- www.birding-aus.org
- --------------------------------------------
- To unsubscribe from this mailing list, send the message
'unsubscribe
- birding-aus' (no quotes, no Subject line)
- to
--------------------------------------------
Birding-Aus is now on the Web at
www.birding-aus.org
--------------------------------------------
To unsubscribe from this mailing list, send the message 'unsubscribe
birding-aus' (no quotes, no Subject line)
to
|
