I followed this thread with some interest, as I used to have Mandarins. I had been told by a local waterfowl expert that it was impossible to interbreed Wood Ducks and Mandarins due to chromosomal differences. Since she had a lot more experience than I, and I was not really interested in turning it into my doctoral thesis, I took her at her word, and due to space limitations I chose not to get any Woodies at that time. The discussion has ranged from here to Red Robin's barn and back, but the gist of the argument, as best I can see it, is "Show me yer papers!" Followed by citations which were not 'specific' enough, which were followed by MORE citations that were again completely ignored, ad infinitum. I am a curious sort, so I did my own research on the matter. But, coming late to the fray I feel certain that any support I might lend to Keith et al would simply be shouted down without those pesky 'sources.' So, in the interests of providing sufficient 'sources' to stop the accusations of 'parroting' hearsay: Here you go.
"Another thought is that ducks of other less closely related genera, and pos-
sibly even of other tribes, may be the source of selective pressures if sufficient
"mistakes" in mate choices are made that involve these more distant relatives.
There is considerable support for this supposition. The Wood Duck is
notorious for forming mixed pairs and has produced hybrids with 26 species
of ducks (Johnsgard, MS). Species involved include such unlikely forms as
the Common Shelduck (Tadorna tadorna), 16 species of Anas, and five
species of Aythya. This would indicate a very high first generation chromo-
somal compatibility, exceeded only by the Mallard (Anas platyrhynchos),
which has hybridized with 40 species of Anatidae. It is of significance that
the majority of Wood Duck hybrids of known parentage have involved the
female Wood Duck, whereas most Mallard hybrids result from the male
Mallard copulating with females of other species.
The hybrids produced by Wood Ducks and Mandarins are apparently
always sterile, and although they have been reported only from birds in
captivity, these facts do demonstrate the Wood Duck's unusual proclivity for
mixed pairing. Mandarins, on the other hand, are not known to have hybrid-
ized with more than five other species. Paradoxically, the two species of Aix
will only rarely, if ever, hybridize with each other. The remarkable findings of
Yamashina (1952), which indicate that the Mandarin possesses two less
chromosomes than the Wood Duck and other anatines, would provide a logical
explanation for sterility in alleged Mandarin X Wood Duck hybrids, and may
also explain the former's failure to hybridize with as many species as has the
Wood Duck."
Source:1-1-1959
Comments on Species Recognition with Special
Reference to the Wood Duck and the Mandarin
Duck
William C. Dilger
Cornell University
Paul A. Johnsgard
University of Nebraska-Lincoln, [email protected]
That seems pretty specific to me.
I really do not get why this needed to be an argument, but since someone seems inclined to scream for 'references!' while declining to offer any, here it is. Oh, and there was also this: According to the canaryzoo.com, "The mandarin duck is the only specie of duck that cannot interbreed due to a different number of chromosomes." So, there you have at least two reputable sources, one of them at least with a doctorate from a peer reviewed paper. If that is unsatisfactory (and somehow, I am just sure it will be) then you may just have to settle for a smoke and a pancake. I found this with very little trouble, in only a few moments' time, on Google. I have no doubt that, given a free afternoon and access to the local library, I could turn up other learned tomes that would say pretty much the same thing. Which would also doubtless be ignored or belittled for not being thorough enough. Ah, well.
"Another thought is that ducks of other less closely related genera, and pos-
sibly even of other tribes, may be the source of selective pressures if sufficient
"mistakes" in mate choices are made that involve these more distant relatives.
There is considerable support for this supposition. The Wood Duck is
notorious for forming mixed pairs and has produced hybrids with 26 species
of ducks (Johnsgard, MS). Species involved include such unlikely forms as
the Common Shelduck (Tadorna tadorna), 16 species of Anas, and five
species of Aythya. This would indicate a very high first generation chromo-
somal compatibility, exceeded only by the Mallard (Anas platyrhynchos),
which has hybridized with 40 species of Anatidae. It is of significance that
the majority of Wood Duck hybrids of known parentage have involved the
female Wood Duck, whereas most Mallard hybrids result from the male
Mallard copulating with females of other species.
The hybrids produced by Wood Ducks and Mandarins are apparently
always sterile, and although they have been reported only from birds in
captivity, these facts do demonstrate the Wood Duck's unusual proclivity for
mixed pairing. Mandarins, on the other hand, are not known to have hybrid-
ized with more than five other species. Paradoxically, the two species of Aix
will only rarely, if ever, hybridize with each other. The remarkable findings of
Yamashina (1952), which indicate that the Mandarin possesses two less
chromosomes than the Wood Duck and other anatines, would provide a logical
explanation for sterility in alleged Mandarin X Wood Duck hybrids, and may
also explain the former's failure to hybridize with as many species as has the
Wood Duck."
Source:1-1-1959
Comments on Species Recognition with Special
Reference to the Wood Duck and the Mandarin
Duck
William C. Dilger
Cornell University
Paul A. Johnsgard
University of Nebraska-Lincoln, [email protected]
That seems pretty specific to me.
I really do not get why this needed to be an argument, but since someone seems inclined to scream for 'references!' while declining to offer any, here it is. Oh, and there was also this: According to the canaryzoo.com, "The mandarin duck is the only specie of duck that cannot interbreed due to a different number of chromosomes." So, there you have at least two reputable sources, one of them at least with a doctorate from a peer reviewed paper. If that is unsatisfactory (and somehow, I am just sure it will be) then you may just have to settle for a smoke and a pancake. I found this with very little trouble, in only a few moments' time, on Google. I have no doubt that, given a free afternoon and access to the local library, I could turn up other learned tomes that would say pretty much the same thing. Which would also doubtless be ignored or belittled for not being thorough enough. Ah, well.
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