Willow Tits in Britain - inbreeding & partial albininism (1 Viewer)

lewis20126 · Nov 5, 2014

GMK said:
Anyway, I am sure that you would prefer to hear from people who have seen Willow Tits with some errant white feathers, which (for the record) I have not.

I seem to recall seeing a partially white Narrow-billed Antwren (Formicivora iheringi) at Boa Nova. That probably wasn't a good sign!

cheers, alan

lewis20126 · Nov 5, 2014

James Lowther said:
i
here is a list of scientific publications including the words "partial" and "albinism" in the title, often together

http://www.ncbi.nlm.nih.gov/pubmed?term=(partial[Title]) AND albinism[Title]

.
"Partial albinism in a semi-isolated population of great reed warblers.
Bensch S, Hansson B, Hasselquist D, Nielsen B"

Relevant in more than one context here.

cheers, a

Farnboro John · Nov 5, 2014

I think the birds in question should be shot and analysed to resolve the issue.

John

lewis20126 · Feb 25, 2017

Willow Tit with white head feathering:

http://www.goingbirding.co.uk/hants/show_photo.asp?speciestype=2&photo_id=8129

A rather striking one! has anyone seen any more?

cheers, alan

Jos Stratford · Feb 25, 2017

GMK said:
Terminology may well have been mis-used, even perhaps to some extent developed through common usage, with the consequence that other birders will perfectly understand ... but that doesn't actually make such usage truly correct.

Over time, if developed through common usage and widely understood, that usage would become the correct usage.

Phil Hill · Feb 26, 2017

We have a small population of Willow Tit in the Cynon Valley in South Wales. A birding friend of mine Martin Bevan has recently had a bird visiting his garden in Aberdare with a white wing on one side and white tail. This is the first time he has notices any plumage differences in the area.

lewis20126 · Feb 26, 2017

Phil

Thanks - so that is at least 4 populations in which white feathering has been recorded in the last few years.

cheers, alan

dantheman · Feb 26, 2017

Will be interesting to see if any aberrant birds are noted on the Cornwall Willow Tit Survey this/next winter -

http://www.cbwps.org.uk/cbwpsword/willow-tit-survey/

wheatearlp · Feb 26, 2017

I saw,two Willow Tits @ Fairburn a couple of weeks ago with white central tail feathers. Perhaps the West Yorkshire population referred to earlier?

Jos Stratford · Feb 26, 2017

lewis20126 said:
Thanks - so that is at least 4 populations in which white feathering has been recorded in the last few years.

If assessing the role of inbreeding, I guess of relevance would be, if such records exist, the incidence of this in the days before Willow Tits became so fragmented.

Widespread occurrence of white feathering in Blackbirds and various crows, etc - these populations presumably not subject to high occurrence of inbreeding.

For what its worth, here where Willow Tits are common, I have never seen birds with abnormal plumage.

Paul Chapman · Feb 26, 2017

The attached paper is historical. It recorded 5 of the 8 Paridae species with instances of albinism but only 14 records (out of 3,134). As a result, considering how frequently the group would have been recorded, this suggests that albinism in the family is very rare (although one of the five species is probably Willow Tit).

All the best

Paul

Paul Chapman · Feb 26, 2017

I am wrong. It happens.

The five species of Paridae are:-
Long-tailed Tit
Blue Tit
Great Tit
Coal Tit
Marsh Tit

See the attached paper which also has a brief discussion of albinism as a result of inbreeding.

All the best

Paul

Andy Adcock · Feb 26, 2017

At a very slight tangent regarding the White-winged Duck in the OP, I thought that the amount of white in the head on Sumatran birds was a racial thing?

A

Paul Chapman · Feb 26, 2017

andyadcock said:
At a very slight tangent regarding the White-winged Duck in the OP, I thought that the amount of white in the head on Sumatran birds was a racial thing?

A

The separate subspecies view is rejected in the attached.

All the best

Paul

lewis20126 · Feb 26, 2017

Paul

Thanks for those attachments, interesting stuff. I wonder if there is some clever person out there who can estimate isolated population sizes from the incidence of partial albinism / leucism?

cheers, alan

dantheman · Feb 26, 2017

lewis20126 said:
Thanks for those attachments, interesting stuff. I wonder if there is some clever person out there who can estimate isolated population sizes from the incidence of partial albinism / leucism?

Norman Whiteside springs to mind as the obvious candidate perhaps?

Jos Stratford · Feb 26, 2017

lewis20126 said:
I wonder if there is some clever person out there who can estimate isolated population sizes from the incidence of partial albinism / leucism?

Maybe I am way off the ball but still not sure that inbreeding is responsible for the partial albinism - whilst I don't doubt that partial albinism could be enhanced by a reduced gene pool, presuming some of those in the limited pool carried the recessive gene, is there any data that shows that this is actually caused by the inbreeding as such?

Additionally, I would guess population size estimate must be difficult, as some species seem far more prone to it than others, ie thrushes, sparrows and crows. So first we would need to work out some sort of incidence rate for each species and then presume it does not vary from one fragmented population to another (and if it the albinism is just due to chance concentrations of birds possessing the recessive genes, I would suppose it would vary). As said, maybe I am just speaking rubbish though

Andy Adcock · Feb 26, 2017

Paul Chapman said:
The separate subspecies view is rejected in the attached.

All the best

Paul

Cheers Paul,
still seems uncertain to me as to exactly what the cause is but I wouldn't say the author 'rejected' the idea of the racial separation of Sumatran birds, he does question it though.

Andy

lewis20126 · Feb 26, 2017

These are examples of suspected links between true albinism and inbreeding from a quick google:

gorilla:

https://blogs.biomedcentral.com/on-...akes-story-a-tale-of-albinism-and-inbreeding/

http://news.nationalgeographic.com/news/2013/06/130618-albino-gorilla-inbreeding-genes-science/

humans: http://www.genetic-genealogy.co.uk/supp/effects_inbreed.html

[check out table 4 at the bottom for increased incidence]

Tigers [leucism]: http://animalethicsri.weebly.com/white-tiger-inbreeding.html

I obviously can't vouch for any of these studies, pages but it seems logical to me.

cheers, alan

lewis20126 · Mar 10, 2017

lewis20126 said:
I've not seen any in the small and isolated population of Willow Tits on the chalk in North Hampshire but I would expect this to happen in the near future.

cheers, alan

I've finally caught up with Hampshire's first (?) Willow Tit with abnormal white bits, the same bird as linked above, see attached for my pic this morning.

cheers, alan

Willow Tits in Britain - inbreeding & partial albininism (1 Viewer)

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