[wisb] Re: Rare Thrush - Green Lake County
- From: "Laura DeGolier" <ldegolie@xxxxxxx>
- To: <cynthiabridge@xxxxxxxxxxx>, <trschultz@xxxxxxxxxxxxxx>, "'WISBIRDN'" <wisbirdn@xxxxxxxxxxxxx>
- Date: Sat, 26 Dec 2009 05:58:15 -0600
If Cynthia is correct, this bird would be suffering from leucism, see
information below posted on Yardbird last year. I had a house finch that was
leucistic..
Therefore the white patches are caused by a defect preventing normal
deposition of the melanin. And since leucism is a deposition problem, it
makes sense that birds with white patches would be leucistic. Consequently
leucism comes in two main varieties - paleness, an equal reduction of
melanin in all feathers; and pied, an absence of melanin in some feathers
creating white patches.
Interestingly, albinism only applies to an absence of melanin. Since some
colors come from other pigments, such as carotenoids, it is possible for a
bird to be albinistic and still have color. Leucism, on the other hand,
applies to all pigments. It is also possible for a bird to be completely
white and still have melanin in the body. In this case the bird would be
considered leucistic and would have dark eyes because the mutation only
applies to depositing melanin in the feathers. Albinistic birds have pink
eyes because without melanin in the body, the only color in the eyes comes
from the blood vessels behind the eyes.
Leucism is rare in birds, and albinism is extremely rare. From 2000-2006,
Project FeederWatch participants reported less than 1000 leucistic birds.
Given that participants report about 5.5 million birds each season, the
percentage of leucistic birds is very, very small.
Laura DeGolier
Fond du Lac
-----Original Message-----
From: wisbirdn-bounce@xxxxxxxxxxxxx [mailto:wisbirdn-bounce@xxxxxxxxxxxxx]
On Behalf Of Cynthia Bridge
Sent: Friday, December 25, 2009 10:52 PM
To: trschultz@xxxxxxxxxxxxxx; 'WISBIRDN'
Subject: [wisb] Re: Rare Thrush - Green Lake County
My thoughts on this bird...a partially albino American Robin.
Cynthia Bridge
Fort Atkinson, Jefferson County, WI
-----Original Message-----
From: wisbirdn-bounce@xxxxxxxxxxxxx [mailto:wisbirdn-bounce@xxxxxxxxxxxxx]
On Behalf Of Tom Schultz
Sent: Friday, December 25, 2009 10:18 PM
To: WISBIRDN
Subject: [wisb] Rare Thrush - Green Lake County
I have to admit it -- my heart was racing a bit when I got a look at this
bird...
We were leaving home around 11:30 AM today to head over to my mother's house
for Christmas when this bird flew up from the ground along my driveway.
Initially it was flying straight ahead of my vehicle (at about a 20 to 30
foot distance), but then it turned left and into some trees, and it appeared
to land. I didn't have much of a look as it was flying ahead of me, but
when it banked and went by me at a more perpendicular angle, I was able to
see that the bird had some VERY unusual and striking markings -- including
what appeared to be a contrasting white eyebrown. I thought, "What the heck
was that!!???", as my mind started racing through the possibilities -- but
nothing seemed to fit.
I was starting to think that this could be something really rare -- like
maybe an Eye-browed Thrush or some other Siberian thrush that had strayed
over from Asia!
I hit the brakes and skidded a bit on the ice before coming to a stop,
grabbed my camera, and got out of the car, and I believed that I was now
about 50 feet past the bird. Although I felt pretty certain I knew about
where it had landed, I couldn't see the bird, and I was really hoping it was
stick around for a second look -- and hopefully some photos.
I walked slowly (but as quickly as possible) back in that direction, and
soon spotted the bird on a branch as I got past a large tree. I snapped a
few shots initially, then others periodically as I slowly tried to stalk
closer. I had gotten out of the car so quickly that I didn't have my
binoculars, so I was hoping that some of my shots would be good enough to
help with a possible ID. The lighting was not great, as there was a light
rain falling, but here are a few shots of this very cool bird -- not
perfect, but also not too bad:
http://www.pbase.com/trschultz/christmas_thrush_25_dec_09
What do you think? As I said, this bird had quite a striking appearance!
(Sorry I wasn't able to post this sooner, but we just returned home this
evening.)
Tom Schultz
Green Lake Co.
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