A large creature found grazing on mushrooms deep underground. It walks on two legs and has the head of a bird with the horns of a great elk.
I've been thinking about the elk bird and I have two issues with it. Actually the problem is the horns, but I have two main problems with the horns.
I imagine elk birds like subterranean moas with antlers. If this is generally correct I'm not very satisfied with them as a concept. The big bipedal birds that we know (emus, ostriches etc) all have in common a very long neck and a small head. A long neck and small head cannot realistically support a great rack of antlers on a two-legged frame and hope to keep its balance easily or maneuver with any speed. If the idea of the horns is defence they defeat the purpose themselves, and if it's display they still can't afford to be too burdensome.
Which leads onto my other problem with antlers on this particular giant bird biped. The elk bird lives underground. Granted the underground of a DF world has vast caverns with high vaulting ceilings where I imagine grows most of the fodder that the elk birds graze on. But the elk birds are a herding animal ([CLUSTER_NUMBER:5:10]) so I imagine that they would over time exhaust the supply of food in one cavern before migrating to a new place. The caverns are connected by narrow twisting tunnels and I think it would be strange if the ceilings of these tunnels weren't very low as often as not. Trying to travel under a low stone ceiling while wearing a rack of antlers would be a nightmare. After the hundreth time getting stuck on a stalactite the elk bird would be smashing it's tines against a wall in frustration until they snapped off.
So what am I suggesting? Get rid of the horns? Pretty much. But then why would it be called an elk bird? Good point. But I don't think an unconvincing animal should be invented simply to fill a cool name. Unless the whole point of the animal is to be strange for the sake of strangeness (like a chimera or something). I love the idea of a large walking bird living underground that can be domesticated and turned into a fearsome mount, I just can't rationalize the horns and any concept of evolution to fit their environment.
So some work arounds I've mulled over in order of my preference:
1. Alter the horns. Instead of great big heavy antlers weighing down the little head and bending the long neck, change them to something like a unicorns horn and change the name to a Lance Bird or whatever fits. This keeps the original concept (the single horn can be used as display or defence) while also probably not being too burdensome underground. The creature could hold it's head so that the light weight horn would be pointed away from a ceiling and keep it that way for a time without tiring. Obviously a bird with a single horn doesn't look as cool as a bird with antlers but it's less ridiculous. If a unicorn horn is too much like a unicorn then change the antlers to something else distintice. Give it a sharp crest and call it a shark bird for example. Anything that could reasonably work.
2. Make the horns seasonal. The birds grow them quickly for the rut and then shed them when it's over.
3. Keep the elk bird exactly as it is but work in some reason for it to be able to exist comfortably as it is. Maybe the elk birds use large tunnels dug out by another species (cave dragons?) to travel around the underground and so they have the luxury of growing antlers.
4. Keep the elk bird as it is but move it to the surface. Antlers will not catch on open sky. And if we ignore the whole weight and balance issue a large set of antlers sounds like an effective deterent against giant eagle attack and thus would be a good excuse for the elk bird to have developed its horns.
I know I've made assumptions about the elk bird people might not agree with so let me know what you think. Maybe you do agree but don't like my suggestions for change and can think of something better.
