Is this a Brant x Canada Hybrid?


On Wednesday 1 January 2003, I came across this unusual goose amongst a large flock of Atlantic Brant feeding on the lawns surrounding Meadow Lake, Corona Park in Queens, New York. In terms of size, structure and behavior, the bird seemed indistinguishable from the surrounding brant. However, several aspects of its plumaged seemed unfamiliar. The bird appeared much browner than any of the other brant including other first-winter birds which can be quite variable and the black head color extended to half way down the neck rather than onto the breast as is the case will all brant forms. Likewise there is no hint of a white neck collar typical of all brant and the white uppertail coverts seem to be of intermediate length. The buff tips to the scapulars and wing coverts suggest a 1st year bird, however the sprinkling of older (darker) coverts leaves this in question. Adult Canada Geese, for example, show buff edges to the upperpart feathers. In these respects, the mystery bird resembles a Cackling Goose, except that it lacks the distinctive white cheek of all Canada Geese. There is however, a faint hint of pale color where this cheek patch would be. Do wild Cackling Geese ever lack cheek patches?

Additional features that seem wrong for a Cackling Goose are:



Outstretched, the black neck sock seems to extend only halfway down the neck.

With waterfowl, hybrids are always an important concern.  I don't think the nesting ranges of Cackling Goose and Atlantic Brant overlap at all, probably not even close. So could hybridization to other (larger) Canada Geese produce such a small product? The presence of a few scattered darker wing coverts might also signal brant genes, showing a lower degree of penetrance compared to those of Canada Goose.


Here is a typical first-year Atlantic Brant photographed on the same afternoon. It can be aged by the broad white tips to the scapulars, coverts and mantle feathers. As with adults, the black of the head and neck extends onto the upperbreast and flanks (the so-called neck sock). Some young brant can be much browner than this one, however none approach the Corona Park bird.


Portrait of an adult Atlantic Brant showing the extent of the black neck sock. If anything, the bill on these two Atlantic Brant seems a little longer than the mystery goose, however, one might expect some sex-based as well as individual variation in bill shape and size.


In Canada Geese, the back neck sock does not reach all the way down the neck, similar to the mystery goose. To illustrate the point, here is a reference photo of a local Canada Goose.

Here are some links to photographs of Cackling Geese. Unfortunately, I don't have any of my own.

http://www.cfo-link.org/cacklingas.html
http://home.att.net/~cobus/cacklinggoose.htm
http://home.wanadoo.nl/leojrboon/bra_min01.htm

Any comments on the Corona park goose would be appreciated.

In strong sunlight the center of the breast shows a darker patch.

On Sunday 5 Jan 2003, the goose was relatively vocal. Its call was distinctive and allowed me easily follow the bird as it moved around in the grazing brant flock. The call resembled the buzzy, nasal note of the brant but had a higher component to it, strongly reminiscent of a Canada Goose!



Expert Comments (in order received)

What a neat bird!  I think you have it right with a hybrid based on a cursory glimpse of the pictures. Reports of Cacklers out of range are troubling to me in the sense that the wild birds don't wander according to band reports. I'm presuming it was hanging out with Brant and no Canadas were around, right? [with brant but some Canada's nearby, AW] Mary Gustafson, Maryland, USA

The photo is stunning and wonderful. I have no earthly idea what the bird is, of course. Ned Brinkley, Virginia, USA

The impression from the head shape is that of a cackling goose and not that much of a brant. It appears that there "must" be some cackling in it. I have never seen cackling hybrids myself, but have seen several greater canada x greylag. One of the most consistent features has been the presence of the white or pale cheeck patch (see http://www.astro.utu.fi/hlehto/photo/ -> hybrids). But having said that I wouldn't be surprised if a cack x brant would look like your bird. The black of the brant may be such a dominating feature that it just swamps any pale areas of the other species! Hybrids can be reminiscent of one of the parents, or in between or have features not present in either parent, so not finding a particular feature present in the parent species does not rule out that species. Harry Lehto, Finland

Very interesting bird! Can't offer you any definite information regards whether it's a hybrid or not, I really don't know? However, based on gut feeling- I'd be surprised if it is not a hybrid or that it is 'just' a Cackling Goose without a chin strap. The head and bill shape/structure look very Brant-like, especially the head. To be more exact, I'd be very surprised that Cackling goose minus the chin-strap= Brant structure and head-shape! My hunch is that it is a hybrid. The plumage is mostly Cackling but structure is Brant. I'd expect the head shape of Cackling to be rather square with a steeper angle to the forehead. Gerard Philips, New York, USA

The funny goose is a corker. Quite obviously a Brent x Canada hybrid, definitely not a funny Cackler. In addition to the points you mention, the upperparts are wrong for minima and show some grey brent-like feathers, the tail/uppertail covert structures are tending towards brent, the bill structure is brenty, leg-length is brent (short tibia), and the dark belly / rear flank crescents are brent influenced. All in all, a fabulous creature! Richard Millington, Norfolk, UK

I had another look at the hybrid goose photos, and thought I'd throw a few more comments your way. As well as the tail/uppertail covert structure being closer to brent than Canada, so is the structure of the secondaries/tertials. In the narrow-winged brents, the secondaries are short and rather equal in length (so form a parallel band along the rear of the closed wing), with the tertials suddenly rather longer. This is a bit wader-like. In the broader-winged Canadas, the secondaries become gradually but noticeably longer inwards, bulking out to meet the tertials, so form a broadening wedge on the rear wing. Your bird is intermediate in this respect too, but closer to Brent. Of course, the other parent probably isn't Cackler. The fact it looks a bit like one now is an artefact; I guess the original Canada parent was one of the middle/northern forms. Richard Millington, Norfolk, UK

Bruce Peterjohn suggested Pink-footed Goose as the second parent rather than Canada. I rather like this suggestion as the bill structure does not seem long as any Canada other than Cackler would likely add to a Brant bill. This isn't as wild a suggestion as it might seem if the flock is
from Greenland or wherever the bird that turns up in PA summers. Cacklers are not rare in captivity in my memory but from the reports I've seen of them in the east I don't even think the subspecies is correct on most--dark small Canadas can be Richardsons/Hutchins geese or even small interiors from the James Bay Islands (and some are best left as dark small Canadas!).  As a birder I'd like to see more attention paid to Canada Goose subspecies in the field (and I see this starting). Mary Gustafson, Maryland, USA

Just saw your pictures of the striking branta goose from Corona Park. I agree with Richard Millington's comments, and Gerard Phillip comments.  Looking at the first photo from the breast down, I would never even have guessed that it had any brant in it at all - to me body and feather morphology say Canada goose. However, the bill is that of a brant. There is no need to involve Cackling Canada geese in any explanation, in my opinion. As far as hybridization and potential parentage is concerned, what no one else has mentioned is that Atlantic Brant nesting in the eastern Arctic (where your NY birds come from) broadly co-exist with Richardson's Canada geese (Branta canadensis hutchinsii). The two species nest in close proximity on Southampton Island, Baffin Island, and elsewhere. Although their breeding chronology is slightly askew (Richardson's nesting earlier by a couple of days), there would be plenty of overlap in the egg-laying and fertile period of females, and plenty of opportunity for extra-species copulation and fertilization resulting in such a hybrid. Its size would therefore not be a surprise, as Richardson's from those islands are larger but not too much so. Thanks for posting the picture, a great looking bird, wish I were close enough to come down and have a look myself. Ken Abraham, Barrie, Ontario, Canada

Ransom (1927) Condor 29:170 reported on a Brant X Canada Goose (hutchinsi) from Washington state. You might want to see what his bird looked like. I've gone both ways on the age of your bird. The rather uniform look to the breast and back (except for the smudging due to introgression?) and wide-looking fathers suggest AHY to me but I'm not confident. Peter Pyle, California, USA

The problem with hutchinsii as a parent is this: they are supposed to be very pale breasted. Now, any kind of blanket statement re: Canada Goose races is suspect. However, for one parent to be hutchinsii, it would have to be an aberrant hutchinsii. Possible, but less likely. See photo in Ogilvie and Young, p. 47. In my experience, this is typical of hutchinsii - with such a bird as one parent, the bird in  question should not have such dark underparts. Steven Mlodinow, Washington, USA

"AW: In life the goose moves and acts very much like a brant,"  Is that brant behavior or tiny goose behavior? "AW: even its odd call contains that distinctive buzzy tone so distinctive of brant.I certainly agree the head and bill shape is more Canada like than brant,prompting me to ask questions about variation in Cackling Goose. It is toosmall and short necked to be a Richardson's. Clearly there are several things wrong for any Canada but brant x Canada cross seems to fit the details". I don't deny it. I having kind of been throwing up my hands at Canada Goose variation lately.  What I ought to do is knuckle down and look at it more closely. As I'm sure you're aware, the subspecies are just a mess, and I personally can't get a solid fix on much of anything concrete to define one. The black throat divider is as good an example as anything, with some people seeming to like it a lot to define some subspecies. But, it seems to pop up (or out) in any of the races, and the few Alaska forms in our drawers don't correspond to what people seem to expect of them. I'm hoping the BNA account will deal with this topic, but it still isn't published. Kevin McGowan, New York, USA

What a terrific bird! - well done on picking this out and getting such good images.  I feel the conclusions of this bird's ancestry are the most plausible - but the shortness of the neck sock is a bit unusual, as it seems even shorter than on typical Richardson's CG.  FYI here a couple of such birds from Fort Worth recently - one of which has an obvious throat divide: http://www.martinreid.com/cago2.html Martin Reid, Texas, USA

These photos illustrate the similar size to brant. Side-by-side the mystery goose stood fractionally taller.



Acknowledgements Many thanks to Andy Guthrie for thoughful comments on the identification of this bird and numerous corrections to the contents of this web page. Also thanks to those listed above, who commented on the photos. As always, I appreciate it!


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