Yeah, I did indeed base it on the American porcupine as I thought it looks more graceful. But now that I think about it, it might be easy to mistake it for a hedgehog (or an echidna). Maybe if I make the hind spines longer it will be more clear.
Besides that, the current version seems to be missing its tail, so fixing that would help. It sort of looks wrong without it, and definitely more hedgehog like-than it ought to.
and it was a LOT more difficult to find reference material with the right angle for birds and fish than for land animals.
Er, you should probably be getting references of these from enough angles to have a general understanding of their body forms. I wonder if this limited breadth of reference images is part of why the peacock turned out wonky.
I think sprites for creatures in a 3D environment being different if fine, but some of the positions are a bit weird on their own.
Particularly the sperm whale making a weird pose (do they ever move their cores that much? Can they, even? The only examples I can find that even kind of look like that are the result of severe foreshortening).
Also a bit weird that the barn owl is sprited in the midst of landing when everyone else is flying. Similarly weird that the vulture has its legs sticking down; not something they normally do in flight.
The two falcon-looking ones (I can't identify more specifically by species, but top left and second from the bottom, also left) look short round and goofy. I know a certain degree of "chibi" is inevitable given that it's quite a small size to attempt recognizable faces on, and that's consistent with most of the other animals (the loon is a notable exception in this batch) but I think you could make them look a lot better by trimming those two pixels of extra chub from their breast. Maybe even bring the more abaft of the two up by a second pixel, to avoid too much of a straight line and to be consistent with how high the tail is? I know it'll mess up the really clean rendering you've done of the facial markings, but I think the silhouette/form of the body is important enough to sacrifice that at this scale.
Also a couple things I'm not too clear about. Of the two that look more or less like vultures, why does one have its legs down? As far as I know, California condors do that, but also don't look like that. I wasn't able to come up with another species that does that in regular flight. So I'm curious what both of the two buzzard-looking fellows are meant to be.
Also the one below the bald eagle, the impression it gave me at first was like an osprey, but the facial markings are wrong and you've been pretty accurate on those for the others, as far as I see. I googled around other related taxa that might fit the body form but didn't see anything appropriate in doing so (or in a cursory google of kite types) so I guess it's just something I'm unfamiliar with.
You are very constrained (inb4 size comparisons[1]) and obviously I await the Premium++ animated versions with [variant motion types]
I don't think that's the sort of thing that will ever be a priority.
You don't [have an osprey] do you? Might not be the sub-species I'm most familiar with if you do. That's my excuse, anyway. Carry on!
I checked the four recognized subspecies, none of them match. The bald eagle is also a sea eagle though, and could prey upon the fish just the same as an osprey would.
That barracuda looks strange and too cartoonish, I thought, not knowing what a barracuda looked like IRL. What a wack animal! No complaints about it, nor the poses.
The impression is because of the angle. They look normal side-on. This one looks a bit more cartoonish because of the ridge Mike added on the back of the head, but aside from that it's accurate (if we assume that the blue color is based on the lighting it's assumed it'll have in its natural environment).