[obol] albino pelicans (and more)

[Dan Gleason]

Cindy,

I have never seen any reference to albinism or leucisim in any  
species of pelican. Albinism is known in just over 300 species of  
North American birds, representing 54 families. Pelicans are not  
included in this list. I remember finding one reference to albino  
pelicans from the Carolina coast that was reported in The Auk in the  
1930s (I can find the exact reference if you wish) but the author  
states that the birds seen were most likely White Pelicans. He noted  
that White Pelicans were quite rare for that region but that the  
presence of more than one albino (I believe that 4-5 birds were seen)  
at the same time and place would be far more improbable (nearly  
impossible, statisically).

Albinism is most common in species that are highly social, or very  
sedentary. Both of these situations favor a strong possibility of  
inbreeding. Birds that are found in loosely associated groups tend to  
have much lower frequencies of albinism.

Albinism has a genetic basis as it is a defect in the gene  
responsible for the production of tyrosinase, the enzyme that  
converts the amino acid tyrosine into a chemical (dopaquinone, if you  
want the name) that is then converted to melanin, the dark pigment. A  
complete albino bird has all white feathers and pink eyes and feet.  
The pink color is the result of no melanin to block the color of the  
hemoglogin in the blood near the surface of the unfeathered parts.  
Partial albinos may produce some melanin in only some portions of the  
body or may produce so little melanin that the normal patterns are  
very pale.

In birds, some complete albinos may actually have some coloration  
caused by pigments other than melanin. Carotenoids cause the red and  
yellow colors found in birds and all of these pigments come from  
plant sources in the diet. They cannot be produced by the bird's own  
biochemistry. This can lead to some very interesting color patterns.  
Imagine a House Finch with the normal reddish color but all of the  
other feathers are completely white - no browns or dark at all. A  
male Hairy Woodpecker would be completely white except for the red on  
the back of the head. Such carotenoid-colored complete albinos exist  
but are rare because complete albinism is also rare.

Dan Gleason
-------------
Dan Gleason
dan-gleason at comcast.net
541 345-0450


On Sep 27, 2007, at 11:35 PM, Cindy Ashy wrote:

> Question: has anyone ever seen a leucistic/albino
> Brown Pelican?
>
> Cindy Ashy
>
>
>        
> ______________________________________________________________________ 
> ______________
> Luggage? GPS? Comic books?
> Check out fitting gifts for grads at Yahoo! Search
> http://search.yahoo.com/search?fr=oni_on_mail&p=graduation+gifts&cs=bz
> _______________________________________________
> obol mailing list
> obol at lists.oregonstate.edu
> http://lists.oregonstate.edu/mailman/listinfo/obol
>
> To unsubscribe, send a message to:
> obol-leave at lists.oregonstate.edu.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.oregonstate.edu/mailman/private/obol/attachments/20070928/cf9f5dae/attachment.htm