Friday 30 May 2014

Eurasian Capercaillie x Black Grouse

Eurasian Capercaillie x Black Grouse hybrid, Sweden?, 6th December 2008 - copyright Carl Gunnar Gustavsson
(photo ID: 1032)


This is one hybrid well enough known to have earnt itself its own name: Rackelhahn.

Carl Gunnar estimates the size of these males to be comparable to a female Capercaillie and describes the behaviour at lek as being rather similar to that of Capercaillie.  He notes the quality of sound as being more growling and lower frequency compared to Capercaillie.  Henry Lehto has also found their calls to be different, citing 8 individuals whose calls were very different from either parent - built from about six detached calls of growling with lower frequency. He notes that the tone could recall Carrion Crow Corvus corone or even Raven Corvus Corax.  A ninth bird apparently sounded more like a Capercaillie.

Carl Gunnar refers to a study (Höglund NH & Porkert J, 1989*) which finds that these birds should be crosses between a male Black Grouse and a female Capercaillie.  Crosses the other way round, male Capercaillie x female Black Grouse, were only possible by insemination (but look the same).  Male hybrids have poor sperm quality but still produced F2-hybrids in an enclosure with a female capercaillie.  Female hybrids exist but were considered sterile.

Apparently female hybrids inherit their colour pattern from the fathers.  Offspring of a male Black Grouse thus lack orangey-brown breast area and have tighter barring whereas the male Capercaillie x female Black Grouse offspring has the orangey-brown breast and broader barring resembling a Capercaillie hen.  The latter hybrid is however presumed not to occur in the wild.

* Experimetal crossing of capercaillie and Black Grouse: Zeitschrift für Jagdwissenschaft 35:221-234


The first Rackelhahn shown here was at a lek.


Eurasian Capercaillie x Black Grouse hybrid (same bird as in photo ID 1032 above), Sweden?, 6th December 2008 - copyright Carl Gunnar Gustavsson
(photo IDs: 1033-1034)


The next one was not at a lek.

Eurasian Capercaillie x Black Grouse hybrid, Sweden?, 6th December 2008 - copyright Carl Gunnar Gustavsson
(photo ID: 1035)


Henry Lehto has contributed that male Rackelhahns have elongated outer tail feathers and so a longer tail in flight compared to Capercaillies.  He thinks the Rackelhahn's body is narrower compared to Capercaillie (breast and body not so heavily built) and so this gives a different shape and enforces the impression of a "longer" tail.  A presumed female hybrid he once saw had the same impression.  The shape of this flying female did not fit female Capercallie.

This male is clearly shorter tailed than Black Grouse but in the flight shot you get a good view of the white wing-bar that's absent in Capercaillie.  Henry notes that these hybrids always show a lilac breast colour despite this being absent on the parent species.





Eurasian Capercaillie x Black Grouse hybrid, Kaskinen (Finland), 30th October 2010 - copyright Henry Lehto
(photo IDs: 2536-2540)


Finally here's one from a museum in Germany:



mounted Eurasian Capercaillie x Black Grouse hybrid (with female Capercaillied), Senckenberg Museum, Frankfurt, Hesse (Germany), March 2015 - copyright Joern Lehmhus
(photo IDs: 2314-2316)



Eurasian Capercaillie Tetrao urogallus
Black Grouse Tetrao tetrix

Common Goldeneye x Smew

Common Goldeneye x Smew hybrid, Rauma (SW Finland), late April or early May 2017 - copyright Henry Lehto
(photo ID: 3221)


Here is a very smart hybrid showing clearly intermediate features of the two parent species, nicely captured (as always) by Henry.




Common Goldeneye x Smew hybrid (same bird as in photo ID 3221 above), Rauma (SW Finland), late April or early May 2017 - copyright Henry Lehto
(photo IDs: 3222-3225)


This one is a museum specimen and as is often the case with such specimens the bill and legs are painted, so not their real colouration.

 

mounted Common Goldeneye x Smew hybrid, shot on the river Oker near Braunschweig (Lower Saxony, Germany) in 1825 - copyright Joern Lehmhus 
(photo IDs: 0595-0596)



Common Goldeneye Bucephala clangula
Smew Mergellus albellus

Golden Pheasant x Lady Amhert's Pheasant

captive (but free-ranging) Golden Pheasant x Lady Amherst's Pheasant hybrid, Pensthorpe (Norfolk, UK), 28th February 2010 - copyright Dave Appleton
(photo ID: 0526)


Some hybrids between these two species are obviously intermediate, some look more like Golden Pheasants and others, like this one, look more like Lady Amherst's Pheasants.  As hybrids are fertile it may be that those that more closely resemble one or other parent species are backcrossed, second or subsequent generation hybirds, but I am currently unclear as to the extent of variation within first generation hybrids.  On this bird the red belly is an obvious and clear sign that it is not a pure Lady Amherst's Pheasant, but whether it is a first-generation hybrid or not I am not sure.


 captive (but free-ranging) Golden Pheasant x Lady Amherst's Pheasant hybrid (same bird as in photo ID 0526 above), Pensthorpe (Norfolk, UK), 28th February 2010 - copyright Dave Appleton
(photo ID: 0527)


The next bird is even more like a pure Lady Amherst's Pheasant, and must surely be a backcrossed bird (though I have no proof of that).  It differs from a pure bird in having the red on the crown extending to the forecrown - on a pure bird it would be greenish black here.  It also shows a faint buffy-red wash on the belly.  I'm told that a large proportion of captive Lady Amherst's Pheasants are in fact impure, with some Golden Pheasant genes from generations back - and the opposite may be true of Golden Pheasants.




 captive (but free-ranging) Golden Pheasant x Lady Amherst's Pheasant hybrid, presumably backcrossed with Lady Amherst's Pheasant, Pensthorpe (Norfolk, UK), 13th March 2010 - copyright Dave Appleton
(photo IDs: 0522-0525)



The next bird may possibly not be a hybrid.  Not all captive-bred Golden Pheasants resemble their wild ancestors, for example an all yellow form is popular, and this may simply be a variant of Golden Pheasant.  The crown is typically redder on hybrids, not paler as on this bird, so that may count in favour of it being a mutant rather than a hybrid, and a desaturation of colour could also explain the whiter ruff.  That could equally be down to Lady Amherst's Pheasant influence, as could the grey legs, but for now the exact identity is uncertain.




free-ranging (presumably escaped) possible Golden Pheasant x Lady Amhert's Pheasant hybrid, or perhaps mutant Golden Pheasant, Happisburgh (Norfolk, UK), 10th November 2011 - copyright Dave Appleton
(photo IDs: 0528-0529)


Some feral populations of Golden Pheasant consist of birds which have extensive blackish colouration on and around the throat.  This is often cited as evidence of past hybridisation (some generations back) with Lady Amherst's Pheasant, but I have not been able to find any clear evidence to back up this idea.  An alternative explanation is that it is caused by a mutation arising as a result of in-breeding, which explains why it occurs mostly in small and diminishing feral populations as well as in captive populations.  One very small population in west Norfolk has long held only dark-throated birds (known as var. obscurus) whereas a larger population in the Norfolk and Suffolk Brecks has historically consisted of normal-looking birds.  The west Norfolk birds are now all but extinct (no more than 2 males reported in the last 2-3 years) but the Breckland population is also rapidly declining.  The last bird I saw in the Brecks had a darker throat than normal.  If further study confirms that this population is indeed becoming dark-throated as it becomes smaller with a more restricted gene pool then that would support the understanding that these birds are mutants and not hybrids.


 feral mutant Golden Pheasant (var. obscurus), Wolferton (Norfolk, UK), 12th January 2010 - copyright Dave Appleton
(photo ID: 1566)

More photos of dark-throated mutant Golden Pheasants (as well as some normal ones) can be found here.


Golden Pheasant Chrysolophus pictus
Lady Amherst's Pheasant Chrysolophus amherstiae

Reeves's Pheasant x Ring-necked Pheasant

Reeves's Pheasant x Ring-necked Pheasant hybrid, Threxton Hill (Norfolk, UK), 17th March 2012 - copyright Dave Appleton
(photo ID: 0517)


The introduced Reeves's Pheasant population in the Norfolk Brecks appears to be increasing rapidly and as is often the case with species populations becoming established in a new area, hybrids appear. In this situation the incidence of hybrids may be increased as a result of a disproportionate number of males among the Reeves's Pheasant population.

The first hybrid shown here had a cyst on the back of the head with large colourful feathers hanging loose from it.




 
Reeves's Pheasant x Ring-necked Pheasant hybrid (same bird as in photo ID 0517 above), Threxton Hill (Norfolk, UK), 17th March 2012 - copyright Dave Appleton
(photo IDs: 0518-0521)


I passed by the copse where I saw this several times over the subsequent months but never saw it again... until nearly 3 years later.  Presumably the same bird as not only in the same place but showing the same tuft of loose feathers at the back of the head.









Reeves's Pheasant x Ring-necked Pheasant hybrid, Threxton Hill (Norfolk, UK), 22nd February 2015 - copyright Dave Appleton
(photo IDs: 2003-2011)


On my next visit the bird was still present, but so was a second bird (more on which to follow further down this page...)  Here's the original one:

Reeves's Pheasant x Ring-necked Pheasant hybrid, Threxton Hill (Norfolk, UK), 21st March 2015 - copyright Dave Appleton
(photo ID: 2149)


Still there in 2016, though I couldn't find it on some intervening visits.  On this occasion it was calling, but a bit too distantly for my sound recordings to have come out usable.

Reeves's Pheasant x Ring-necked Pheasant hybrid, Threxton Hill (Norfolk, UK), 27th March 2016 - copyright Dave Appleton
(photo ID: 2768)


Reeves's Pheasant x Ring-necked Pheasant hybrid, Threxton Hill (Norfolk, UK), 19th November 2016 - copyright Dave Appleton
(photo ID: 2847)


A friend had seen the second bird a few weeks earlier and described it to me - I wondered if it was a hybrid between a Reeves's Pheasant and a tenebrosus variant of Ring-necked Pheasant.  Tenebrosus Pheasants are the very dark birds that seem to be released among the more normal-plumaged Ring-necked Pheasants quite often - there are lots in this area (photos of a male here and a female here and more at gobirding.eu).  Well now I've seen it I still think that's the most likely ID.  The Reeves's influence isn't very strong in this bird's plumage - although very clear in the structure - notably the long tail but also I think the thick-necked puffed out look probably comes from Reeves's Pheasant (it reminded me of pictures of Chicken x Pheasant hybrids, but not with that tail!).  When I saw it first it was displaying on the very same log that the previous hybrid was displaying on when I first saw it back in March 2012.  I suppose it's plausible that rather than this simply being a second hybrid it's the offspring of the hybrid, presumably crossed with a Tenebrosus Pheasant - but how likely is it that this inter-generic hybrid is fertile to be able to produce a backcross?






presumed Reeves's Pheasant x Ring-necked Pheasant (var. tenebrosus) hybrid (or perhaps the previous hybrid backcrossed with a Tenebrosus variant Ring-necked Pheasant?), Threxton Hill (Norfolk, UK), 21st March 2015 - copyright Dave Appleton
(photo IDs: 2150-2155)


The next bird was rather distant and only on view very briefly, hence the substandard photo.

 
Reeves's Pheasant x Ring-necked Pheasant hybrid, Great Cressingham (Norfolk, UK), 27th February 2011 - copyright Dave Appleton
(photo ID: 0516)



Reeves's Pheasant Syrmaticus reevesii
Ring-necked Pheasant Phasianus colchicus