I tend to agree with Onorio Catenacci, however I can't ignore the fact that it doesn't seem to either topics being really used. On the other hand, I don'tthink that they should be on Biology or Outdoors either. Perhaps, a joint .SE for /wildlife/ could be the solution, as it would mean that Bird Lovers, Fishers, Fishcaretakers, People who like to watch Squirrels and Racoons could all be fit in one place, amd as such, having a better chance at succeeeding.
As such, yes, I do believe that Orthonology is too narrow, but not because it's a small field, but because the interest shown, or rather, the quantity of users attracted hasn't been enough to warrant a Beta. As such, I'd suggest having a Wildlife.SE instead, that would cover both the already mentioned activities and others in the same area