Tundra Bean Goose x Greater White-fronted Goose

probable Tundra Bean Goose x Greater White-fronted Goose hybrid (with Tundra Bean Geese), Oost (Texel, Netherlands), 29th December 2016 - copyright Diederik Kok

(photo ID: 3004)

Convincing examples of hybrids between some of the wild Anser species that occur in Europe are surprisingly hard to come by.  Perhaps that is because the hybrids are genuinely scarce, or perhaps it is hybrids are difficult to detect and even harder to prove, with variation in parent species considerable.  I suspect it's the latter but maybe in time this will become more clear.  This one looks like a promising candidate to me, although proving it is not an odd but genetically pure Tundra Bean Goose is not straightforward.

The white round the base of the bill is not enough on its own to reject pure Tundra Bean Goose - quite often they have a little white round the bill.  Usually this is broken on pure birds, not surrounding the whole of the upper mandible in a continuous line.  Not only is it continuous here but it's quite broad at the top too.  Perhaps that is possible in pure Tundra Bean - it wouldn't surprise me if so - but this bird also has a lot of dark shading behind the white, something that I don't recall seeing to this extent on a Tundra Bean Goose.  The extent of orange on the bill may not be too excessive for Tundra Bean Goose (though is not usual) but it also seems to have a pinky tone to it.  I think in combination these features point to a likely hybrid origin, although I am troubled by how perfect the rest of the bird looks for Tundra Bean Goose.  Maybe it is just a very unusual Tundra Bean Goose, but I am more convinced by this bird being a hybrid than others I've seen where the hybrid ID has been suggested.

In addition Diederik thought this bird called differently from the Tundra Bean Geese.  He has a recording of it at waarneming.nl.  I think it's quite a subtle difference, but that may be because I don't hear Tunrda Bean Geese calling often enough!

As always, comments are welcome!

probable Tundra Bean Goose x Greater White-fronted Goose hybrid (same bird as in photo ID 3004 above; with Tundra Bean Geese), Oost (Texel, Netherlands), 29th December 2016 - copyright Diederik Kok

(photo ID: 3005)

Tundra Bean Goose Anser serrirostris (formerly Anser fabalis rossicus)
Greater White-fronted Goose Anser albifrons

Great Blue Heron x Great Egret

Great Blue Heron x Great Egret hybrid, Fort de Soto Park, Pinellas County (Florida, USA), 17th August 2016 - copyright Dave Norgate

(photo ID: 2976)

The long kinked neck of this intriguing bird is very much like that of a Great Egret, but in other respects the structure of this bird seems to resemble Great Blue Heron as much.  The grey plumage and the bill do not belong on a Great Egret, whereas the yellow lores must come from an Egret species.  The latter, along with the neck structure, help rule out Würdemann's Heron (the hybrid or intergrade between Great White Heron (the white form occidentalis of Great Blue Heron that occurs in southernmost Florida) and typical Great Blue Heron.

Thanks to Steve Mlodinow for pointing out that this bird has been accepted as this hybrid by eBird reviewers and photographed by other observers over six months.

Great Blue Heron x Great Egret hybrid (same bird as in photo ID 2976 above), Fort de Soto Park, Pinellas County (Florida, USA), 17th August 2016 - copyright Dave Norgate

(photo IDs: 2977-2986)

Great Blue Heron Ardea herodias
Great Egret Ardea alba

Common Goldeneye x Hooded Merganser

Common Goldeneye x Hooded Merganser hybrid, Ottawa River (Ontario, Canada), 26th October - copyright Gordon Johnston

(photo ID: 2997)

Goldeneye sp. x Hooded Merganser hybrids are fairly frequently reported in the wild and broadly speaking this is a typical plumage for either.  The majority of reports probably relate to Common Goldeneye x Hooded Merganser.  The head colour seems to reflect that of the Goldeneye parent species at least in many instances, but you can't really make that out here.  However the extent of white in the scapulars helps clinch this one as involving Common Goldeneye rather than Barrow's Goldeneye.

We already have a page featuting a probable female Goldeneye sp. x Hooded Merganser which, in view of the extent of yellow on its bill is possibly more likely to involve Barrow's Goldeneye.


Common Goldeneye Bucephala clangula
Barrow's Goldeneye Bucephala islandica
Hooded Merganser Lophodytes cucullatus

Great Egret x Snowy Egret

Great Egret x Snowy Egret hybrid, Fort de Soto Park, Pinellas County (Florida, USA), 18th August 2016 - copyright Dave Norgate

(photo ID: 2987)

Dave says this bird seemed intermediate in size between Great Egret and Snowy Egret.  Structurally it seems to have an intermediate neck length and shape - you can see a hint of the kinked shape of Great Egret in some of the photos but it's not as clear as in a pure bird.  The bare parts also seem to be consistent with expectations for this hybrid.  Certainly the legs are wrong for Snowy Egret being entirely black right down to the bottom of the feet.  The gape line only extends back to below the cetnre of the eye, just like it does on Snowy Egret.  On Great Egret it would extend right back to beyond the back of the eye.  The only pure species I could possibly turn this into is Intermediate Egret, which in some respects it quite closely resembles.  However, although the Asian form of Intermediate Egret apparently does adopt a black bill in breeding condition (I don't believe the African form does) this bird is showing no sign of being in breeding condition.  I don't think the bill structure is quite right for Intermediate Egret either, and of course an Asian Intermediate Egret is rather unlikely in Florida - there are one or two ABA-area records but only from the Aleutian Islands in western Alaska so far as I know.

Great Egret x Snowy Egret hybrid (same bird as in photo ID 2987 above), Fort de Soto Park, Pinellas County (Florida, USA), 18th August 2016 - copyright Dave Norgate

(photo IDs: 2988-2991)

Great Egret Ardea alba
Snowy Egret Egretta thula

Little Blue Heron x Tricolored Heron

Little Blue Heron x Tricolored Heron hybrid, Hammonasset State Park (Connecticut, USA), 23rd July 2013 - copyright Len Blumin

(photo ID: 2917)

Len makes a good case for the hybrid ID of this interesting bird.  Initially I was not entirely convinced but thought it was worth putting out there for others to comment on, and to see if other birds like this come out of the woodwork.  Turns out it was worth it as more information came to light.

As Len says, this bird's posture and structure resembles that of a Tricolored Heron, and of course much of the plumage does too.  Apparently some think the bill is intermediate in structure between Tricolored and Little Blue - a bit too subtle for my eye if so.  The obvious anomaly for pure Tricolored in terms of plumage is the grey belly and thighs (better seen on the photos below) - Tricolored should be pure white here.  Len has considered if this might be melanism but thinks this is unlikely on feathers that should be pure white.  I wasn't so sure about that - certainly there are records of normally white herons that have appeared grey, although at least some of these have been contaminated rather than being genuinely melanistic.  Nevertheless, in some cases they had a very even covering of grey and contamination was not obvious, so I was not completely convinced that we could rule that out in this case.

There are a couple of other features that Len points to that support Little Blue Heron involvement.  One of those is the iris colour which Len describes as pale yellow, or straw yellow.  It's normally brown, red or pink on adult Tricolored Heron.  I think a pale yellow iris is ok on immature Tricolored Heron (but Len's bird doesn't show any signs of juvenile plumage) - is it ok in an adult?  I don't get to see many Tricolored Herons, being in the UK, so trawled through some images online.  On some birds the majority of the iris seems to be yellowish but surrounded by pink or red on the outside of it, while on others even that wasn't very clear, such as this one.  So wasn't quite sure about this - did this really rule out pure Tricolored Heron?

Finally Len also draws attention to the manner in which it was feeding.  He writes, "The bird foraged rather deliberately looking for fish, as we often see with the Little Blue, whereas the usual Tricolored foraging is often more active, even frenetic, recalling the fishing technique of the Reddish Egret cousin."

So, I wondered, is there enough to call this a hybrid, or is it more likely a very odd but genetically pure Tricolored Heron?  Well, it turns out there were 2-3 birds seen in the area in the autumn of 2011 which superficially resembled first calendary-year Tricolored Herons but with anomalies including excessive white in the plumage.  They continued into the following year and some observers recognised that the white in the plumage might be a result of hybridisation with Little Blue Heron, noting an intermediate bill structure.  However it was hard to be sure that the white wasn't down to leucism until the birds were seen again later on in 2012 and in subsequent years.  Just as Little Blue Herons of this age would turn from white to grey, the amolous features of these birds (or at least one of them) had turned from including too much white to too much grey.  The evidence for them being hybrids with Little Blue Heron had suddenly became a lot stronger.  The records have now been accepted on eBird as this hybrid.  Thanks to Steve Mlodinow for drawing my attention to this, and you can read about it more on Nick Bonomo's website and see photos of one of the birds in their second calendar-year.

Little Blue Heron x Tricolored Heron hybrid (same bird as in photo ID 2917 above), Hammonasset State Park (Connecticut, USA), 23rd July 2013 - copyright Len Blumin

(photo ID: 2918)

Little Blue Heron x Tricolored Heron hybrid (same bird as in photo IDs 2917-2918 above), Hammonasset State Park (Connecticut, USA), 28th July 2013 - copyright Len Blumin

(photo IDs: 2919-2920)

Little Blue Heron x Tricolored Heron hybrid (same bird as in photo IDs 2917-2920 above), Hammonasset State Park (Connecticut, USA), 31st July 2013 - copyright Len Blumin

(photo ID: 2921)

Little Blue Heron Egretta caerulea
Tricolored Heron Egretta tricolor

Warbling Vireo x Red-eyed Vireo

Warbling Vireo x Red-eyed Vireo hybrid, Lone Dome SWA, Montezuma County (Colorado, USA), 24th May 2016 - copyright Steve Mlodinow

(photo ID: 2876)

Steve points out the rather long, hooked bill, olive hues to the ear-coverts and the dark lateral crown line to fairly deep grey crown as indicating the Red-eyed Vireo heritage.

Warbling Vireo x Red-eyed Vireo hybrid (same bird as in photo ID 2876 above), Lone Dome SWA, Montezuma County (Colorado, USA), 24th May 2016 - copyright Steve Mlodinow

(photo ID: 2877)

Warbling Vireo Vireo gilvus
Red-eyed Vireo Vireo olivaceus

Black-chinned Hummingbird x Broad-tailed Hummingbird

Black-chinned Hummingbird x Broad-tailed Hummingbird, Longmont, Boulder County (Colorado, USA), 8th July 2015 - copyright Steve Mlodinow

(photo ID: 2878)

Steve picked up on this bird as being rather different from Black-chinned Hummingbirds. He writes:

"The primary tips are distinctly narrower, a bit straighter.  The back color is actually rather like that of a Broad-tailed Hummingbird, which would explain the narrow, straight primary tips.  And... the inner primaries do not form a straight line, but start to widen after P4 or so, consistent with a non-Archilochus parent. Such as a Broad-tailed."

Black-chinned Hummingbird x Broad-tailed Hummingbird (same bird as in photo ID 2878 above), Longmont, Boulder County (Colorado, USA), 8th July 2015 - copyright Steve Mlodinow

(photo ID: 2879)

Black-chinned Hummingbird Archilochus alexandri
Broad-tailed Hummingbird Selasphorus platycercus

Recent updates (or in this case, not so recent updates)

Sedge Warbler x Eurasian Reed-Warbler hybrid, Lac de Grand-Lieu (Loire-Atlantique, France), 6th September 2015 - copyright Sébastien Reeber

(photo ID: 2745)

Firstly let me apologise for the inaction here over the last few months.  Last year proved more hectic than I imagined and keeping on top of this became impossible for a while.  The good news is I'm now in a position to get things moving again, so look forward to more regular posts once again in the near future - and a big backlog to clear first.


I normally do a "recent updates" post periodically to let people know what's been added to the project since the last "recent updates" post.  Well there have been a few updates since the last "recent updates" post, but it's stretching things a bit to call them recent!

As always, a big thanks to all who have contributed photos and/or insights, and if you haven't done yet or have more to offer 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 updates are summarised below but remember you can find an index list linking you to ALL the bird hybrids featured so far here:

• Index of bird hybrids

And an index list of all the bird hybrid topics covered so far here:

• Index of bird hybrid topics

So, the not-so-recent updates are:


New Bird Hybrid pages added for:

• Mute Swan x Black Swan
• Chiloe Wigeon x Cape Teal
• Northern Shoveler x Garganey
• Black-headed Gull x Mediterranean Gull
• Sedge Warbler x Eurasian Reed-Warbler

New photos added to:

• Intersex birds (and their confusion with hybrids)
• Mute Swan x Whooper Swan
• Greater White-fronted Goose x Cackling Goose
• domestic Greylag Goose x Canada Goose
• Snow Goose x Cackling Goose
• Ross's Goose x Barnacle Goose
• Ross's Goose x Cackling Goose
• Dark-bellied Brent Goose x Black Brant
• Ruddy Shelduck x Common Shelduck
• Eurasian Wigeon x American Wigeon
• American Wigeon x Mallard
• American Black Duck x Mallard
• Mallard x Northern Pintail
• Mallard x Red-crested Pochard
• Yellow-billed Teal x Marbled Teal
• Red-crested Pochard x Common Pochard
• Ferruginous Duck x Tufted Duck
• Bufflehead x Common Goldeneye
• Reeves's Pheasant x Ring-necked Pheasant
• Black-headed Gull x Mediterranean Gull
• Yellow-rumped Warbler intergrades ('Myrtle Warbler' x 'Audubon's Warbler')
• Western Meadowlark x Eastern Meadowlark
• European Goldfinch x Island Canary

Text updated in:

• Galah x Little Corella

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

Enjoy browsing - and please do contribute where you can!

Northern Shoveler x Garganey

Northern Shoveler x Garganey hybrid, Mai Po (Hong Kong), 16th March 2016 - copyright John Allcock

(photo ID: 2750)

This interesting bird was consorting with Northern Shovelers and a female Garganey.  Note how the vermiculated rear flanks seem to extend to beneath the tail, which may not be expected.  A quite similar pattern is shown on the Shoveler x Garganey hybrid illustrated on plate 35 of Sébastien Reeber's new Wildfowl book (Helm, 2015).  But the long hanging black-and-white scapulars are a sure sign of Garganey influence.  A faint hint of Garganey's pale supercilium also seems to be just visible in front of the eye.

Northern Shoveler x Garganey hybrid (same bird as in photo ID 2750 above), Mai Po (Hong Kong), 16th March 2016
- copyright John Allcock

(photo IDs: 2751-2752)

Northern Shoveler Anas clypeata
Garganey Anas querquedula

Sedge Warbler x Eurasian Reed-Warbler

Sedge Warbler x Eurasian Reed-Warbler hybrid, Lac de Grand-Lieu (Loire-Atlantique, France), 6th September 2015 - copyright Sébastien Reeber

(photo ID: 2745)

Here is a rare but not unprecedented Old World Warbler hybrid.  This individual is clearly intermediate between Sedge Warbler and Reed Warbler.  The head/bill profile seems rather Reed Warbler-like to me but the pale supercilium is broader and more extensive than on Reed Warbler, while less clear than on Sedge Warbler.  The dark eye-stripe is clearer than you would expect on a Reed Warbler and in some photos you can see a narrow lateral crown stripe (upper border to the supercilium).

The upperparts colour tone is close to Reed Warbler but this bird has obviously dark centres to the wing feathers with contrasting pale edges - especially obvious on the tertials which are quite wrong for Reed Warbler.  Note too the strength of colour on the rump.  A hint of dark streaking in the scapulars is visible on one or two of the images, though these are way plainer than they should be on a fresh Sedge Warbler.  It seems to have some pale buffy coloiur extending into the collar which I would not expect to see on a Reed Warbler.  I'm not a ringer so may be misinterpreting the spread wing shot (below), but I think the way the the tip of the second primary (the outermost long primary) falls well short of the adjacent third primary is closer to Reed Warbler than Sedge Warbler (somebody please correct me if I am wrong about that).

It is sometimes said that this hybrid may be misidentified as a vagrant Black-browed Reed-Warbler.  Some hybrids may look more like that species but I don't think you would make the mistake on this individual.  The Sedge Warbler x Reed Warbler hybrid from Finland that featured in British Birds 78: 434-437 (Sharrock, 1985) has a more obvious head pattern and looks like it had plainer wings too, so some individuals may perhaps be more like Black-browed Reed-Warbler than this one.

Probably a tougher ID challenge is separating these from Sedge Warbler x Marsh Warbler hybrids.  That's a hybrid that has been proven to occur in Norway - see Journal of Ornithology 151.2: 513 (Lifjeld, Marthinsen, Myklebust, Dawson & Johnsen, 2010).

Sedge Warbler x Eurasian Reed-Warbler hybrid (same bird as in photo ID 2745 above), Lac de Grand-Lieu (Loire-Atlantique, France), 6th September 2015 - copyright Sébastien Reeber

(photo IDs: 2746-2749)

Sedge Warbler Acrocephalus schoenobaenus
Eurasian Reed-Warbler (Reed Warbler) Acrocephalus scirpaceus
Marsh Warbler Acrocephalus palustris
Black-browed Reed-Warbler Acrocephalus bistrigiceps