m20 Terror Birds

I have to believe that everyone loves a good terror bird; extinct apex predators native to South America, and the only apex predator that moved into North America during the Great Faunal Interchange (on the other hand, various dogs and cats, including sabertooths, migrated the other direction.  And various herbivores, including ground sloths and more migrated north too).  The largest species would have been as much as 10 feet tall, weighed 400 to 500 lbs, and been speedy, deadly, hawk-beaked killers that would have had an almost dinosaurian aspect, especially now that we know most dinosaurian predator lineages (and in fact maybe the entire dinosaur clade) had feathered representatives.

Now, neither Fantasy Hack nor Dark•Heritage 2.1 has terror birds, but this is another great example to show how quick and easy it is to make modifications to monster stats.  My first thought was that I'd simply reskin some existing stats of some existing creature and call it a terror bird, and that can still be done, if desired.  My second thought was to modify the Dinosaur, Raptor stats to make them slightly unique.  So first, the raptor stats:

DINOSAUR, RAPTOR: AC: 15 HD: 4d8 (20 hp) AT: bite +4 (2d6), 2 claws +4 (2d8), STR: +5, DEX: +3, MND: -4
Smaller, cursorial hunting dinosaurs, that often group into packs for more efficient (and dangerous) hunting strategies.

Smaller being relative to carnosaurs, which are big predators like T. rex or Allosaurus.  Still up to relatively large-sized animals; comparable in many respects to a bear in terms of damage, AC, HP, etc.  (Bears have a bit more hit points, but that seems reasonable, given that they are sturdy animals that are well-known for their ability to shrug off shots from anything other than extremely high powered, high caliber weapons.)  The raptor stats obviously represent a bigger animal like Dakotaraptor or Utahraptor, not a smaller one like Troodon or Velociraptor.

Compared to a raptor, the terror bird has a much more powerful head and bite, but lacks the toe-claw attack which is the signature raptor hunting strategy.  Rather, the claws would probably be blunt and hoof-like, for running across the grasslands of South America, West Texas or Florida, where the fossils have been found.  It could no doubt deliver a nasty kick, but it doesn't have sharp claws.  I think lowering the claw damage, renaming it kick damage, and upping the bite damage is appropriate to make a more terror bird-like stat-line.  Keep the relatively high STR and DEX scores, and the very low MND score; that seems appropriate for a bird, which would probably look and behave much more like a raptor dinosaur than any kind of mammal anyway.

TERROR BIRD: AC: 15 HD: 4d8 (20 hp) AT: bite +4 (3d6), 2 kicks +4 (d8 each), STR: +5, DEX: +3, MND: -4
Apex predators of the prehistoric grasslands, these fast-moving, hard-biting birds are taller than a man, and very dangerous.

It seems to me that the major missing thing I need, especially as I migrate into having Western Hack, is some kind of speed.  If I have lots of mounted chases and whatnot, then all monsters should have a speed score too; otherwise, how do you compare running a Chase with a PC mounted on a horse (and for that matter, how do you distinguish between different breeds of horses, if desired) without having some kind of speed stat?  It would only come into play during chases, I think, but you can't have meaningful chases without it either.  Just using DEX as a substitute for speed is, I think, not optimal from any perspective other than keeping rules bloat from happening.