Canada Goose with head tuft

I saw a what looked like a male Canada Goose pursuing a female. The male has a peculiar tuft on his head. Has anyone seen this before?

Here is another view:

I've seen similar tufts on hybrid ducks... perhaps that is an avenue for explanation?

That's not right. Some kind of skin tumor?

I think Jim DeWitt is spot on, in the sense that the term "tumor" means literally "a swelling or lump"! As a veterinary pathologist (Ret.) with particular interest in wildlife diseases and more than two decades of specific interest in avian diseases I must say I've never seen such a lesion in any bird. However, the feathers growing at the site in question are of a size and pigmentation quite different from those normally produced in that species in that particular feather tract. It thus is strongly suggestive of a congenital anomaly (which could include, but probably doesn't in this case, a genetic mutation) resulting from displacement of cells from a site destined to be in another another feather tract to this site early in embryonic development, probably within the first day or two of incubation. Without the opportunity of thoroughly examining the affected tissues under a microscope, I can only suspect that this is, in technical terminology, an example of a epidermal heterotopic pterylogenic hamartoma ( a mass characterized by anatomically displaced but otherwise normal and functional skin and feather follicles from another feather tract). There is another condition ( which IS documented in birds) characterized by the growth of multiple feathers from a single feather follicle. However, in this condition of follicle polypterylosis the basic features of the feathers so produced as regards pigmentaion and size are generally consistent with others produced in the same feather tract, save for some physical deformations associated with developmental crowding in the distended follicle.

Yeah. That was probably overkill, as my grad students and residents used to say....

Dave Graham, South Dakota

Dave, thank you for that fascinating information. I have heard of dermoid cysts and teratomas containing hair and other structures in humans, probably similar to what you are talking about. Anyway I am reassured, the growth is benign and has apparently not affected his acceptance by the other geese -- in fact the females may even find his tuft quite dashing!

David,

I've never seen so many 10 dollar words, I'm impressed

While I know virtually nothing of the biology of these things, I do know that I see odd tufts on some hybrid domestic ducks. Now, I don't know how a correlation could be drawn to a Canada Goose, BUT here is a photo of one such head tufts. Same thing? Totally Different?

Thanks, Luke,
It's more than a little interesting that the tuft on your pekin is placed identically to the position of the tuft in the Canada goose!

Caveat lector !!! The following is purely speculation !

The identical position of the tufts in these two birds makes one think about the fact that that portion of the head is the one most likely to touch, rub, or bump directly against the inner embryonic membrane (amnion) - and indirectly against the minimally cushioned inner surface of the shell - during incubation. If some viable epidermal cells with the potential to develop feather follicles were displaced from another feather tract to flost randomly in the amniotic fluid, the possibility may exist that such a displaced fragment of epithelium could be traumatically implanted at a site of common touching, rubbing, or bumping of the occipital region of the head.
Pretty neat theory, actually....sort of proud of it...actually...especially at this hour of the night...but, alas, totally unproven.

Dave Graham

Dave,

Glad to see your mind operates even in the latest of hours.

Your theory sounds quite good, but I'm wondering why this tuft looks appears at a higher frequency in domestic or hybrid ducks vs. wild populations (speculation based on personal observation). I've only noticed this in ducks at local ponds and parks that are heavily visited by humans. I have seen it in Pekings and Mallard hybrids (mallard X black duck) as well as some other odd combos. I don't think I have photos of any of them (they were foolishy deleted) but I'll keep my eye out for them.

Perhaps, going with your theory, the larger or "non-normal" size of the hybrids during incubation would cause this part of there head to rub up against the egg at a much higher percentage than in wild populations. Do I see the foundations of a scientific paper?!

- Luke

I just ran into another example, problably a hybrid of some sort. The tuft is placed in exactly the same spot: http://tinyurl.com/ygvlmnp