Another waterfowl fact. This one is gonna be brief. In the previous article we looked at the wing spurs of Plectropterus. They’re pretty cool, but they’re far from unique, and even more incredible are the much larger, dagger-like spikes seen in screamers…
Screamers (Anhimidae) are a small group (three species) of South American* waterfowl… well, they’re not referred to as ‘waterfowl’ as often as are other members of Anseriformes, but I think they should be. One species (Horned screamer Anhima cornuta: shown in adjacent illustration) has – as you might guess – a horn! (though, technically speaking it’s not a horn at all). Anyway…
* Fossil species are known from North America and Europe.
The wing spikes are pretty impressive; they’re long enough to be really obvious even when the birds have their wings completed folded. In the Black-necked or Northern screamer Chauna chavaria [carpometacarpus shown here], a big, curved spike projects from the base of the alula, and a separate, stouter, straighter claw grows from the distal end of the major metacarpal. During combat, the birds will stab rivals with these spikes, and on occasion the spikes snap off and can then remain lodged in the tissues of the opponent. Does this render the attacker spike-less for the rest of its days? NO – the spikes can grow back. Many sources state this latter fact, but I’ve never seen any ‘good’ data on it: how long does it take the spikes to grow back? Do they break off frequently? Do all species suffer from this breakage? I’d love to know more [photo of Southern screamer C. torquata below by Mo Hassan; stolen without permission from here on The Disillusioned Taxonomist. The wing spikes in this species are smaller than those on C. chavaria].
I’ve mentioned the clubs and spikes present on some bird wings a few times now, but have never properly elaborated. Do not fear, as elaborating is what I am going to do in a soon-to-appear article. Stay tuned.
Another waterfowl fact next! For previous Tet Zoo entries on waterfowl see…
- Tet Zoo picture of the day # 10 (on Swan goose)
- 2007: a good year for terror birds and mega-ducks
- Meteoroid vs goose… again
- Attack of the flying steamer ducks
- STOP ‘feeding’ the ducks
- Harbour seal kills and eats duck
- Ridiculous super-elongate, coiled windpipes allow some birds to function like trombones – - or is it violins?
- Duck humps dog, and other stories from the world of waterfowl sex
- Lo, for I have seen the Meller’s duck, and it was good
- The Madagascar pochard returns (again)
- Pink-headed duck and Red-crested pochard: who would win in a fight?
- Duck sex: to interfere, or to watch?
- Can you raise reindeer on goose shit? Amazing waterfowl facts part I
- Death by toxic goose. Amazing waterfowl facts part II