Monday 21 December 2015

Greater Scaup x Lesser Scaup

apparent Scaup hybrid, possibly Greater Scaup x Lesser Scaup, Eyebrook Reservoir (Leicestershire, UK), 10th November 2015 - copyright Andy Mackay
(photo ID: 2415)


This is a difficult bird!  I've included it under the two-Scaup heading but I'm by no means sure that is the correct ID, and acknowledge that others are leaning more towards a hybrid involving Tufted Duck (e.g. on Andrew Harrop's excellent blog), while others suspect it could be a pure Lesser Scaup.  Andy tells us that the pale subterminal band on the bill was more obvious in life than it is in the photos (more of which appear below) - and that is one good reason to consider Tufted Duck as a parent.  Many Tufted Duck x Scaup hybrids show more black on the tip of the bill, but apparently some don't, so that is not a strong enough reason to eliminate Tufted Duck from the equation.  Of more concern to me is the paleness of the back.  Typical Scaup x Tufted Duck has a much darker back lacking such coarse vermiculations as shown by this bird.  Again this does seem to be a variable feature on Tufted Duck x Scaup hybrids, however I have yet to see clear evidence that any Tufted Duck hybrid can show such a pale back as this.  A hybrid backcrossed with Scaup would be another matter, and that must remain a possibility for this bird (though a backcross to Lesser Scaup is surely beyond the bounds of reasonable possibility in the UK?).

The coarseness of the vermiculations suggest (to me at least) Lesser Scaup involvement, and indeed the bird looks a lot like a Lesser Scaup in many respects.  Andy tells me that in the field pure Lesser Scaup was never really a contender, but from the photos I think it would be a very easy conclusion to reach.  For Andy though, he saw it flap its wings twice and observed that the white bar definitely extended across the primaries as in Greater Scaup or Tufted Duck, and of course wrong for pure Lesser Scaup.

Andy also provided the following pertinent information:
"It was at least Tufted Duck size, perhaps slightly larger, and the head shape was nearer Greater Scaup, but usually with an obvious peak on the rear crown (really just a 'rough' patch of feathers interrupting the smooth curve). Also the head was strongly glossed green at all times, with just a hint of purple when seen head-on."
Worth noting that the new Helm guide to Wildfowl of Europe, Asia and North America by Sébastien Reeber has two Tufted Duck x Greater Scaup hybrids illustrated (one head only), one showing restricted black on the bill tip.  Both show a more obvious tuft than the Eyebrook bird had.  If they are the same birds illustrated in his 2002 article "Identification des fuligules et de leurs hybrides" (Ornithos 9: 177-209) then they were both darker-backed birds too.  Gillham & Gillham (Hybrid Ducks - a contribution towards an inventory, 1996) describe two male Tufted Duck x Greater Scaup hybrids as having bodies like Greater Scaup, but they suggest that these birds, which also had rounded heads and were as large as Greater Scaup) might have been backcrossed with Greater Scaup.



apparent Scaup hybrid, possibly Greater Scaup x Lesser Scaup (same bird as in photo ID 2415 above), Eyebrook Reservoir (Leicestershire, UK), 10th November 2015 - copyright Andy Mackay
(photo IDs: 2416-2418)


My first thought when I saw these photos was, "Why isn't this a Lesser Scaup?", so I was interested to receive an email from Steve Mlodinow, one of North America's leading birders and with a great deal of experience identifying hybrids, asking just that, or at least, "Besides the green on the head, why is not this a Lesser Scaup?" A green head sheen isn't enough to discount Lesser Scaup - I've personally seen green-headed birds in both UK & America, albeit eventually they showed purple under prolonged observation.  Steve went on to say,
"The head shape and bill are well within range for [Lesser Scaup], and I don't really see that bill coming out of a Greater Scaup x Tufted Duck hybrid... though I've not looked at known photos of that cross.  Ring-necked Duck x Scaup hybrids have far darker backs than this bird, and I would expect Tufted Duck x Greater Scaup to be similar."
So it seems Steve's interpretation of the photos is akin to mine.  But of course the answer to, "Why not a Lesser Scaup?" has to do with Andy's observations, rather than anything that is clearly visible in the photos.  Having said that, my own observations of both live birds and photos suggest that the wing-bar feature can be difficult to apply in poor or brief views (or imperfect photos).  Steve echoed these sentiments: "Depending on lighting, the wingstripe can be deceiving." But of course neither I nor Steve actually saw the bird, whereas Andy did, and asides from noting the possibility of error in recording wing-bar pattern in a general sense, we are in no position to question Andy's observations.  And it's worth remembering too that Andy thought the bill pattern did not look right for Lesser Scaup in life, showing too pale a subterminal mark.

Well, I shared this feedback with Andy and he's kindly supplied some more photos taken a few days earlier when the bird was more distant.  Here's what he said,
"The photos I sent might be misleading as regards the head shape, because in the field it really didn't suggest Lesser at all.  The attached three heavily cropped images were taken when I first saw the bird the week before, but much further away, and I think give a truer idea of the bird's usual head shape - much more evenly rounded and Greater Scaup-like.  I think if those were the only photos I'd got, no-one would even be mentioning Lesser as a possibility!

This is definitely the same bird, by the way - in the field I noted the occasional appearance of a slight tuft, strong green gloss to the head and that pale band behind the nail, all of which were also seen on the second occasion when it was much closer."
Well, this bird certainly does seem to be something of a mystery!  If nothing else it does provide a great example of why we should be cautious about identifying birds from photos...




apparent Scaup hybrid, possibly Greater Scaup x Lesser Scaup (same bird as in photo IDs 2415-2418 above), Eyebrook Reservoir (Leicestershire, UK), 1st November 2015 - copyright Andy Mackay
(photo IDs: 2450-2452)


Andy and I would both be interested to hear other people's views on this bird, so please let us know if you have any thoughts.



Tufted Duck Aythya fuligula
Greater Scaup Aythya marila
Lesser Scaup Aythya affinis

Thursday 17 December 2015

Recent updates

apparent Clay-colored Sparrow x Brewer's Sparrow hybrid, Kinney SWA, Lincoln County (Colorado, USA), 4th May 2015 - copyright Steve Mlodinow
(photo ID: 2245)


Well, after an extended break while I've been busy with other things I've now caught up on the backlog of photos and contributions that have been provided over the summer - loads of new material!  Thanks to all who have contributed photos and/or insights, and if you haven't done yet then please get in touch.  You can comment on any thread if you have anything to say about the hybrids or topics covered, and if you have any photos you would be willing for us to use, please let us know (e.g. by emailing us).


The recent batch of updates are listed below but remember you can find an index list linking you to all the bird hybrids featured so far here:
And an index list of all the bird hybrid topics covered so far here:



So, the recent updates are:


New bird hybrid pages added for:

New photos added to:

Photos added to bird hybrid topic page:



Don't forget you can now follow us on Twitter at @BirdHybrids


Enjoy browsing - and please do contribute where you can! 

Wednesday 16 December 2015

Western Meadowlark x Eastern Meadowlark

presumed Western Meadowlark x Eastern Meadowlark hybrid, Lower Latham Reservoir, Weld County (Colorado, USA), 21st March 2016 - copyright Steve Mlodinow
(photo ID: 2770)


Steve wites:
"This bird was making a continuous burbling noise (not the flight song of Western Meadowlark) that doesn't fit either species, though I gather can be given by either.  The call was much like that of a Western Meadowlark.

The very black and white head and nape striping is rather unusual for Western Meadowlarkas is the dark center to the one fully visible greater wing-covert and the rust-tinged black bordered tertial.  Excepting confluenta, the subspecies from the Pacific NW, those features are rather atypical for Western Meadowlark.  However, these features are all typical for Eastern Meadowlark.  The yellow malar extent is definitely more Western Meadowlark-like.

These photos were shared with 3 excellent and well-respected field-ornithologists. One said "Eastern Meadowlark" even after examining specimens, another said "Western Meadowlark", and perhaps the wisest, said "ugh!"

Since ~1% of meadowlarks at the zone of contact are hybrids, and we are not far from said zone of contact, occasional hybrids in Colorado are not unexpected.


presumed Western Meadowlark x Eastern Meadowlark hybrid (same bird as in photo ID 2770 above), Lower Latham Reservoir, Weld County (Colorado, USA), 21st March 2016 - copyright Steve Mlodinow
(photo IDs: 2771-2772)


Steve photographed the next bird, a juvenile (or juvenile transitioning to first-winter plumage), in an area where nominate Eastern Meadowlarks used to breed.  He says,
"This bird's tail appeared totally white on the outer 3 tail feathers (r6 is outermost, so r6 thru r4) and there is a substantial amount of white on r3.  This tail pattern is more consistent with Eastern Meadowlark, but probably is within the realm of possibility for Western Meadowlark.  The central tail feathers are barred brown without any dark brown along the shaft, which is consistent with Western Meadowlark (or Lilian's Eastern).  The dark post-ocular stripe is dark and equal in darkness to the lateral crown stripe.  From what I can tell from specimens, juvenile Western Meadowlark should have a paler and more diffuse post-ocular stripe.  This combination of features is intermediate between those of Eastern Meadowlark and Western Meadowlark and would seem to suggest Eastern Meadowlark x Western Meadowlark.  Molt-timing apparently eliminates juvenile Lilian's.


apparent Western Meadowlark x Eastern Meadowlark hybrid, Logan side of Jumbo Reservoir, Logan County (Colorado, USA), 14th August 2015 - copyright Steve Mlodinow
(photo IDs: 2301-2303)



Western Meadowlark Sturnella neglecta
Eastern Meadowlark Sturnella magna
Lilian's Meadowlark Sturnella magna lilianae

Northern Cardinal x Pyrrhuloxia

captive Northern Cardinal x Pyrrhuloxia hybrid, near Tuscon (Arizona, USA), 7th December 2010 - copyright Steve Mlodinow
(photo ID: 2215)


Three different examples of this hybrid here showing a mix of features from either parent.  According to the Handbook of Avian Hybrids of the World (McCarthy, 2006) this hybrid has occurred in the wild in Arizona as well as at the Arizona-Sonora Desert Museum where I think these photos were taken.


captive Northern Cardinal x Pyrrhuloxia hybrids, near Tuscon (Arizona, USA), 7th December 2010 - copyright Steve Mlodinow
(photo IDs: 2213-2214)



Northern Cardinal Cardinalis cardinalis
Pyrrhuloxia Cardinalis sinuatus

Thayer's Gull x Iceland Gull

presumed Thayer's Gull x Iceland Gull hybrid, Sequim, Clallam County (Washington, USA), 10th February 2008 - copyright Steve Mlodinow
(photo ID: 2203)


The taxonomic treatment of Thayer's, Kumlien's and Iceland Gulls has been very confusing but currently many authorities treat Kumlien's (kumlieni) as a race of Iceland Gull (nominate glaucoides) and Thayer's (thayeri) as a distinct species.  Thus "Iceland Gull" is sometimes used (as here) to refer to the whole species (i.e. glaucoides plus kumlieni) and sometimes to refer to just glaucoides (as distinct from Kumlien's).

I don't mind admitting that I was a bit surprised to see a claim of Thayer's Gull x Iceland Gull, even with the qualifying "presumed".  There is enormous difficulty in separating the two species (at least from the perspective of a European who isn't a gull expert), there is uncertainty as to the range in variation of each taxa and there are unresolved questions over what the taxa even are (i.e. does the kumlieni race of Iceland Gull represent introgressive hybridisation between Thayer's Gull and nominate Iceland Gull?).  But from Steve's much better informed and experienced perspective, thayeri and kumlieni are different taxa no matter how you slice it, and so there should still be intergrades or hybrids.  And, he says, this is what he thinks one would look like.  Well that seems fair to me, and I'm certainly in no place to argue against it!

presumed Thayer's Gull x Iceland Gull hybrid (same bird as in photo ID 2203 above), Sequim, Clallam County (Washington, USA), 10th February 2008 - copyright Steve Mlodinow
(photo ID: 2204)


For an overview of the situation with Thayer's, Kumlien's and Iceland Gulls, this page from the Gull Research Organisation is helpful.



Thayer's Gull Larus thayeri
Iceland Gull Larus glaucoides
Kumlien's Gull Larus glaucoides kumlieni

Tuesday 15 December 2015

Dark-eyed Junco intergrades - Grey-headed Junco x Red-backed Junco

Dark-eyed Junco intergrade ('Grey-headed Junco' x 'Red-backed Junco'), Flagstaff (Arizona, USA), 10th December 2002 - copyright Christian Nunes
(photo ID: 2327)


Christian tells us that the Juncos on the on the Kaibab Plateu of northern Arizona are a hybrid swarm of Red-backed x Grey-headed.  For this bird he notes a standard Red-backed Junco plumage but a mostly pink bill.


(See also: Slate-coloured Junco x Oregon Junco, Oregon Junco x Pink-sided Junco, Pink-sided Junco x White-winged Junco, Pink-sided Junco x Grey-headed Junco)
 


Dark-eyed Junco Junco hyemalis 
'Grey-headed Junco' Junco hyemalis caniceps-group 
'Red-backed Junco' Junco hyemalis dorsalis

Clay-colored Sparrow x Brewer's Sparrow

Apparent Clay-colored Sparrow x Brewer's Sparrow hybrid, Kinney SWA, Lincoln County (Colorado, USA), 4th May 2015 - copyright Steve Mlodinow
(photo ID: 2247)


Steve describes how he concluded that 'hybrid' seems the best solution for this intriguing bird:
"The gray underparts, gray face, dull supercilium and eyering, and nape streaking all favor Brewer's Sparrow.  The bill size, white throat, strong malar and moustachial, and bit of buff on flanks fits Clay-colored Sparrow.  This combiantion doesn't fit with Timberline Brewer's Sparrow, which is somewhat intermediate between typical Brewer's and Clay-colored Sparrow, leaving Clay-colored Sparrow x Brewer's Sparrow as the best solution."


Apparent Clay-colored Sparrow x Brewer's Sparrow hybrid (same bird as in photo ID 2247), Kinney SWA, Lincoln County (Colorado, USA), 4th May 2015 - copyright Steve Mlodinow
(photo IDs: 2244-2246)



Clay-colored Sparrow Spizella pallida
Brewer's Sparrow Spizella breweri
Timberline Brewer's Sparrow Spizella breweri taverneri

Townsend's Warbler x Black-throated Green Warbler

Townsend's Warbler x Black-throated Green Warbler hybrid, Crow Valley, Weld County (Colorado, USA), 2nd September 2015 - copyright Steve Mlodinow
(photo ID: 2283)


Best I let Steve explain this one...
"This bird's initial appearance is in the eye of the beholder.  Many will see Townsend's Warbler, as its cheek and crown are black and there is extensive yellow below the black throat.  However, the black throat expands laterally to join the side streaking, not as much as in Black-throated Green Warbler but more so than in Townsend's Warbler.  The auricular patch is narrower, particularly towards rear, than in Townsend's Warblerand the yellow crescent below the eye is larger.  The olive back was utterly unstressed, as in Black-throated Green Warbler but wrong for adult male Townsend's Warbler.  Interestingly, both adult male Townsend's Warbler and Black-throated Green Warbler have gray uppertail coverts and an olive rump that are streaked.  Finally, the undertail coverts are unstressed, a rare finding in Townsend's Warblerat any age, and particularly so in adult males."
Steve refers to a paper in the Journal of Avian Biology, "Hybridization between Townsend's Dendroica townsendi and black-throated green warblers D. virens in an avian suture zone" (Toews, Brelsford and Irwin, 2011) (Journal of Avian Biology 42: 434-446).  Steve tells us that the authors found that only 4 of the 137 birds scored to phenotype by were “intermediate” with most largely resembling one parent or the other.  And there's apparently more information on this hybrid in "Two recent records of apparent Black-throated Green Warbler x Townsend’s Warbler in Colorado" (Mlodinow, Walbek and Leatherman, 2014) published in Colorado Birds 48: 102-106.



Townsend's Warbler x Black-throated Green Warbler hybrid (same bird as in photo ID 2283 above), Crow Valley, Weld County (Colorado, USA), 2nd September 2015 - copyright Steve Mlodinow
(photo IDs: 2284-2286)


Townsend's Warbler Setophaga townsendi (formerly Dendroica townsendi)
Black-throated Green Warbler Setophaga virens (formerly Dendroica virens)

Blue-winged Teal x Green-winged Teal

Blue-winged Teal x Green-winged Teal hybrid, Jasper Road and US287, Boulder County (Colorado, USA), 20th April 2014 - copyright Christian Nunes
(photo ID: 2350)


When they show closely these can be really attractive hybrids!  See this link for a shockingly beautiful example.



Blue-winged Teal Anas discors
Northern Shoveler Anas clypeata

American Wigeon x Northern Shoveler

American Wigeon x Northern Shoveler hybrid, Firestone Gravel Pits, Weld County (Colorado, USA), 17th May 2015 - copyright Steve Mlodinow
(photo ID: 2254)


This seems to be quite a rare hybrid - not only is it our first here but Steve tells us that it was also not an available selection on eBird.  For American Wigeon Steve draws attention to the green head band, the buff chest and the blue on the bill (and I think the white on the upper wing-coverts may also point to Wigeon involvement).  For Shoveler Steve points to the bill shape, the deep orange sides and the grey upper wing-coverts.





American Wigeon x Northern Shoveler hybrid (same bird as in photo ID 2254 above), Firestone Gravel Pits, Weld County (Colorado, USA), 17th May 2015 - copyright Steve Mlodinow
(photo IDs: 2252-2253)




American Wigeon Anas americana
Northern Shoveler Anas clypeata

Mallard x Mottled Duck

female Mallard x Mottled Duck hybrid (behind, with male Mallard in front), Orleans Parish (Louisiana, USA), 19th April 2015 - copyright Steve Mlodinow
(photo ID: 2239)


Steve draws our attention to the buf face and the dark body plumage on this female.  In addition, he tells us, the tail was entirely brown.

A word of caution when identifying this hybrid - Andy Engilis has been in touch with Steve with regard to one of his Mallard x Mexican Duck hybrids to say that research his team have been conducting is showing that a lot of plumage attributed to hybrids in Hawaiian, Mexican and Florida Mottled Duck are incorrect.  We await publication of this research but in the meantime some caution would be advised.



Mallard Anas platyrhynchos
Mottled Duck Anas fulvigula

Monday 14 December 2015

Eurasian Wigeon x Eurasian Teal

probable Eurasian Wigeon x Eurasian Teal, east Gotland (Sweden), 16th April 2015 - copyright Fredrik Ström
(photo ID: 2375)


Fredrik sent me these fine images earlier this year and they appear to be Wigeon x Teal hybrids.  Given their location I assume they are Eurasian Wigeon x Eurasian Teal, though the resemblance to Steve's American Wigeon x Green-winged Teal hybrid is quite striking.

The two images here show different birds that were together.

 probable Eurasian Wigeon x Eurasian Teal, east Gotland (Sweden), 16th April 2015 - copyright Fredrik Ström
(photo ID: 2376)



Eurasian Wigeon Anas penelope
Eurasian Teal Anas crecca

Sunday 13 December 2015

Back in play!

Well, after a far longer pause than I had intended, I've started updating this project again with the first of many photos that folk have been providing us with over the summer.

So far I have just updated the hybrid geese and swans, but I have a backlog containing many more types of hybrid to upload over the next few days.  The latest updates is kept up to date with details of what's been added to the project, and remember there's an index of all hybrids covered here.

New photos are always welcome so please get in touch if you have any to share, and by all means use the comments boxes at the end of each page if you have any comments to make about any of the hybrids covered.

Trumpeter Swan x Tundra Swan (Whistling Swan)

Trumpeter Swan x Tundra Swan (Whistling Swan) hybrid, Burlington, Skagit County (Washington, USA), 5th December 2009 - copyright Steve Mlodinow
(photo ID: 2209)


Here is another of Steve's hybrid records that could very easily have gone undetected were it not for a sharp pair of eyes.  Steve writes:
"This bird had a bill more like a Trumpeter Swan, was intermediate in size between two species, had more yellow on bill than Trumpeter Swan (which can have a dash of pallid yellow in lores), and displayed like a Trumpeter Swan. It was refound a couple weeks later and was paired with a Trumpeter Swan."


Trumpeter Swan x Tundra Swan (Whistling Swan) hybrid (same bird as in photo ID 2209 above), Burlington, Skagit County (Washington, USA), 5th December 2009 - copyright Steve Mlodinow
(photo IDs: 2207-2208)



Trumpeter Swan Cygnus buccinator
Tundra Swan Cygnus columbianus
Whistling Swan Cygnus columbianus columbianus

Greylag Goose x Emperor Goose

probable Greylag Goose x Emperor Goose hybrid, Manor Park, Glossop (Derbyshire, UK), 27th August 2015 - copyright Steve Graby
(photo ID: 2277)


I found this bird a challenging one to identify and started off down the wrong path, but Joern came to our rescue and came up with a good argument for an answer I had not considered.  I had suspected Snow Goose involvement but Joern pointed out that the scaly pattern, the white tail and the uniform dark neck coloration rather point to an Emperor Goose hybrid instead.  As he says, the scapulars appear very straight, without much curve as in many Snow Goose hybrids, but also fitting to Emperor.

Joern also pointed out that the white blaze does not necessarily indicate one of the White-fronted Geese were involved, as Steve and I had both imagined.  Joern reminds us that it can also appear in the cross between a mainly white-headed species (in this case Emperor) and a grey-headed species.  Joern's attention to detail also came of assistance here as he spotted the orange on the bill visible in one or two of the following photos, but which I had overlooked.  This rules out the White-fronted Geese and brings Greylag Goose in to play.

There remains the possibility that the grey goose parent was a domestic bird of mixed Greylag Goose/Swan Goose ancestry, rather than a pure Greylag Goose.




probable Greylag Goose x Emperor Goose hybrid (same bird as in photo ID 2277 above), Manor Park, Glossop (Derbyshire, UK), 27th August 2015 - copyright Steve Graby
(photo IDs: 2278-2281)



Greylag Goose Anser anser
Emperor Goose Anser canagicus or Chen canagica