that's about right. let's get into the other stuff that makes this guy up.
first of all, how about its environment? the text doesn't state anything clearly (but 1E critters often did not). what sort of environment would flightless birds be found in? ostriches and such?
breaking it down:
"The tybor are a race of flightless birds that, when running at maximum speed, seem to “float” above the ground without touching it."
is there any use for this other than unusual flavor text?
"The tybor attacks physically with its two claws and a beak slash. Its magically sharp beak is +3 to hit."
for that +3 to hit, that would be similar to, say, a unicorn's horn right?
"However, it prefers to use its spell-casting ability in combat (or to avoid combat) whenever possible. Tybor are able to employ magic-user spells at the 20th level of ability. They can use nine 1st-level spells, eight 2nd-level spells, seven of the 3rd level, six of the 4th, five of the 5th, four of the 6th, three of the 7th, two of the 8th, and one of the 9th level during any given day. (Spells should be determined randomly by the DM for each individual creature.)"
fairly clearly arcane spellcasting, as a 20th-level caster, and as we agreed on above should be a sorcerer.
"In addition to these spells, the tybor can cast both Haste and Slow spells (no saving throw for either type) four times a day."
covered by what GrayLinnorm said.
"It is rumored that the feathers of the tybor are magical in nature, but only if plucked from a live creature. (DMs are encouraged to make some of the feathers small magical tokens; for instance, a feather might grant the owner the ability to use a Haste spell 3 times a week without the aging side-effect. But not all feathers from a single bird should be magical.)"
sort of a magic item then?
"The tybor have their own language, but never use it in communication with other creatures. They know the tongues of all birds and flying reptiles, and have a limited form of telepathy whereby they can communicate with most humanoids."
what bird/reptile langauges should we know about?
