White Birds - photos and discussion

General birdwatching discussion, help with bird identification, and all other things relating to wild birds and birding in NZ that don't fit in one of the other forums.
Suzi
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Re: Leucistic Birds - photos and discussion

Postby Suzi » Mon Nov 16, 2009 8:38 pm

Hi there,

I know partially leucistic or albinisitc (??) Blackbirds occur irregularly in the population - at least they do around Auckland.

I wondered if anyone had studied a white-marked Blackbird to see if this albinism?? is transferred genetically to offspring and to what extent ? I've not studied genetics beyond college biology, so I'm unsure if this albinism is subject to the same probabilities as normal recessive/dominant gene combinations ? Or is it a random genetic mutation ?

In the past week I've seen a male Blackbird at Waimauku with a ring of white feathers around it's neck, and a female Blackbird in Rothesay Bay with white wing primaries and white on the nape. I'm hoping I can study at least one of them this breeding season to see if they produce any white-marked offspring. Just out of curiosity 8-)

Happy birding, Suzi
molesunlimited
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Re: Leucistic Birds - photos and discussion

Postby molesunlimited » Tue Nov 17, 2009 2:57 pm

Blackbirds with varying amounts of white are commonplace in Cornwall Park/One Tree Hill.

The most extreme example I have spotted was a female with a white head and neck and odd amounts of white flecked through her body. She had nested in the trees east of the Greenlane gate and presumably may have contributed to some of the white flecked birds in the Park today.

Only have poor pics of the female. Very nervous bird. Disliked coming out from under the tree canopy.
blackbird male odd white feathers oth 061124 2262 small.jpg
blackbird male odd white feathers oth 061124 2262 small.jpg (93.85 KiB) Viewed 5537 times
blackbird whiteheaded female cornwall park 060924 0667 small.jpg
blackbird whiteheaded female cornwall park 060924 0667 small.jpg (98.13 KiB) Viewed 5537 times
Suzi
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Re: Leucistic Birds - photos and discussion

Postby Suzi » Tue Nov 17, 2009 5:07 pm

Interesting pix. Especially the albino eye on the female.

Those Cornwall Park Blackbirds look perfect for a study.

Best regards,
Suzi
molesunlimited
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Re: Leucistic Birds - photos and discussion

Postby molesunlimited » Wed Nov 18, 2009 7:37 am

There is a great gene study there. All it needs is a kind philanthropist with research funds to spare and an interest in boids.

Haven't seen that female for a couple of years altho' I don't get down to that area of the park these days as much as I used to. Anyone else spotted her?
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Peter Frost
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Re: Leucistic Birds - photos and discussion

Postby Peter Frost » Wed Nov 18, 2009 8:42 am

We have recorded various aberrant-coloured birds in Wanganui over the past few years: leucistic Australian Magpie and Mallard; Blackbird and Tui with varying amounts of white in their plumage; and, most recently, a pastel-coloured Tui, similar to that shown by Neil Fitzgerald on his website, a bird that he calls ‘leucistic’ (see http://www.neilfitzgeraldphoto.co.nz/gallery/displayimage.php?album=47&pos=35). All this prompted me to look around to try and understand better the taxonomy and causes of plumage discolouration in birds. The most useful and accessible reference is an article by Hein van Grouw titled “Not every white bird is an albino: sense and nonsense about colour aberrations in birds” (Dutch Birding 28: 79-89, 2006, available online at http://www.vogelringschier.nl/DB28%282%2979-89_2006.pdf). In this article, he points out that terms such as albino and leucistic are frequently misused. He goes on to discuss the various genetic, nutritional, and biochemical factors influencing coloration in birds. Plumage colours in birds are determined by the melanines (eumelanin, responsible for black, grey, and dark brown colours, and phaeomelanin, which produces reddish-brown colours; both are under genetic control) and carotinoids (red and yellow pigments derived from a bird’s diet). He describes the factors that can produce colour variations, and provides some useful definitions of the different terms.

Albino—a total lack of both melanins, due to the complete lack of the enzyme tyrosinase, which catalyses the oxidation of tyrosine, the initial step in the formation of melanin.
Leucism—a partial or total lack of eumelanin and phaeomelanin in the feathers, due to an inherited disorder that prevents the deposition of these pigments in the feathers.
Brown—a qualitative reduction of eumelanin due to a mutation that causes incomplete oxidation of tyrosine, affecting eumelanin’s appearance, but not its amount; phaeomelanin is not affected.
Dilution—a reduction of amount of melanin, producing either pastel-coloured plumage if both eumelanin and phaeomelanin are reduced, or isabel-coloured plumage if only the amount of eumelanin is reduced.
Ino—a marked qualitative reduction in both eumelanin and phaeomelanin, producing very pale brown feathers where they should be black.
Schizochroism—in which one or other of the two melanins is completely reduced, leading to phaeo-schizochroism (no eumelanin) or grey schizochroism (no phaeomelanin).
Melanism—an increase in melanins, producing a bird that is either black all over (eumelanism, due to an increase in eumelanin), or overall reddish-brown (phaeomelanism, due to an increase in phaeomelanin).
Differently coloured—all other inheritable colour aberrations, including grizzle (partially pigmented feathers) and acromelanism (temperature- and environment-dependent deposition of melanins).
Without knowing the extent of change in the two melanins, something that would need to be determined biochemically, it may be difficult to distinguish unequivocally between some of these types.

To the extent that any or all of the aberrations in melanin production have a genetic component, then it may be worth documenting the incidence of aberrant-coloured birds, given the potential for high UV radiation levels experienced in NZ (a consequence of the stratospheric ‘ozone hole’) and its potential to damage DNA. If, as is likely, the potential for genetic damage is real, then we might expect an increase in the incidence of plumage discoloration over time, at least as long as the ‘ozone hole’ persists. For species such as Blackbird, which were introduced from the northern hemisphere, where the seasonal ozone hole is not yet as well developed as that in the southern hemisphere, it might be interesting to compare the incidence of aberrant-coloured individuals in both hemispheres. We should have a higher incidence. (There is still the possibility that a higher incidence here could be due to genetic drift, a result of the small founding population, but let’s leave that discussion for another time.) In short, the incidence of aberrant-coloured individuals may be an indicator of UV-induced genetic damage. Keep recording :)

Peter Frost
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Tony Whitehead
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Re: Leucistic Birds - photos and discussion

Postby Tony Whitehead » Fri Dec 18, 2009 10:54 pm

This swan is currently at the lakefront in Rotorua. I presume leucistic with a very attractive even patterning.
LeucisticBlackSwanTW7_6213BNZweb.jpg
Leucistic Black Swan
LeucisticBlackSwanTW7_6213BNZweb.jpg (57.56 KiB) Viewed 5525 times
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Neil Fitzgerald
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Re: Leucistic Birds - photos and discussion

Postby Neil Fitzgerald » Sat Dec 19, 2009 10:26 am

Looks an awful lot like the one that was at Taupo a few months ago. I hadn't seen it for a while and was wondering where it might have gone.
nbf_Cygnus-atratus_10877.jpg
nbf_Cygnus-atratus_10877.jpg (53.51 KiB) Viewed 5520 times


A couple of other angles

I don't know the intricate details of the various causes of whiteness, but the bit of research I did lead me to think this might be partial leucistic, and the tui and kereru I've seen leucistic. I don't mind being convinced to call them something else.
Neil.
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Tony Whitehead
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Re: Leucistic Birds - photos and discussion

Postby Tony Whitehead » Sat Dec 19, 2009 1:22 pm

I was also struck by the similarity to the image on your website, Neil. The patterns seems a bit different on a similar view I have to yours with less white on the flank and maybe more on the neck. May have changed a little with moulting though. Either way it would be interesting to know if it had migrated from Taupo or whether there are actually 2 similar individuals. I don't remember ever seeing anything similar in swans but have seen a few partial leucistic Blackbirds and a full leucistic Mynah that had a very similar colouration to your Tui.
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Re: Leucistic Birds - photos and discussion

Postby andrewcrossland » Sun Jan 10, 2010 10:51 am

Hi folks,

I'm working on a paper on an albino spotted shag recently, and have a few requests for info.

firstly, has anyone got a copy (or have access to read a copy) of "Falla, R.A. 1932. Records Auckland Museum 1: 139-145". I'd like to know the full title of the paper and info, including locality of the albino Pied Cormorant he reported.

Aside from Falla's Pied Cormorant, 2 little cormorants reported by Moisley at Clevedon (in Notornis 1960), an albino Spotted Shag at Kakoura (Buller 1891, 1892 trans & Proc NZ Inst) and an albino Black Cormorant from Sumner, CHCH (Buller 1874, trans & Proc), can anyone point me to any other albino or leucistic cormorant/shag reports in NZ?

The pic below is an albino Spottted I photographed at the Ashburton Rivermouth - a very impressive-looking bird!
albino spotted shag.jpg
albino spotted shag.jpg (138.82 KiB) Viewed 5509 times
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Glen Webber
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Re: Leucistic Birds - photos and discussion

Postby Glen Webber » Sat Mar 24, 2012 3:05 pm

Thought I'd add this pic to the collection here. Bellbird photographed on Tiri this week.

Image

Cheers,
Glen.

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