Not really a bug report, more of criticism with many of the mobs in the mod and how miserable they make my life while playing with the mod, but i don't know where else to report this.
The mod seem to have aged like milk today, from a mods that was in almost every modpack under the sun, to now a mod nobody else is wanting to add to their modpacks, and i can see why, the mobs aren't so vanilla friendly after all, and many of them aren't just a terrible nuisance for gameplay, and others are quite broken, and the mod seems to have stopped development entirely after alex's caves, which is a shame, they don't have to add more content, just fix the problems with the current content.
Personally i still really like the mod and many of its mobs, so i give my own personal criticism about some of the mobs in hope Alexander Mobiles eventually listen and _make those stupid fkin seagulls leave me the fk alone OMFG!_ plus some extra ideas i have for the mobs (note this is only based on what i experienced so far, i haven't gotten to the nether or end in a playthrough with the mod yet so i can't talk about the annoying dimensional mobs i heard of, in case you have bad experiences with them feel free to share them here) 

• Grizzly bears:

Their aggro range is way too big, they start attacking me practically the moment i get in their sight, not to mention that they're near impossible to outrun and deal insane damage, to the point where i had to enter creative and kill those two f#@$ bears to get my stuff back, wasn't their point to be animals that you're just not supposed to approach? maybe make they not chase but just attack if you get right next to them? and they only start chasing if hit or you approach the cubs, also they could get red eyes like naturalist's brown bears, i think that would be cool.
An hybrid with polar bears would be a neat idea.

• Seagulls:

Yeah i know those birds are known for being the spawn of satan around beaches, but this is to the point where i have to exterminate all those fkers on sight and avoid beaches entirely, i'm also scared of them stealing any rare food like golden apples/carrots and modded ones. Make it so they only steal food from the ground and our hand, rather than just pickpocketing straight from our inventory. Maybe they could even steal food while we eat, that seem quite fun, and yeah might still be annoying BUT STILL MILES BETTER THAN TAKING FROM OUR INVENTORY JUST BY COEXISTING WITH THEM AND FOLLOWING US TO KEEP STEALING MORE AAAAAAAAAAHHHHHH

• Bison:

Probably the mob in the game i want to get reworked the most, they're a really cool concept of a beefier cow that also gives unique wool, but they'll also attack if you get right next to them, but they really don't fit in vanilla, all the other mobs have models that make they feel straight up officially part of the game, but those fkers have an ugly abnormally larger than any cow model that doesn't even have eyes, not to mention that their behaviour is also broken, if i hold wheat they will come rushing toward me and attack because they get right close to me, this is just... insanity. i doubt any bison is like that, i heard mooses are insanely big in real life, but i'm sure for bison they're just slightly bigger than cows, and guess which of them is the biggest in the mod.
So please, just rework them entirely, their ugly huge models, their behaviour of rushing at us at mac speed and attacking whenever we hold wheat, also they could have a charging attack when actually aggroing us when attacked or we approach their young, like naturalist's rhinos, which btw could also be added to the rhinos from the mod, i think it would be a super cool idea, better than they just attacking like any regular mob.

• Crow:

They have been overall fine, except for the fact that if you have both a crow and parrot in your shoulder they'll overlap each other which is really weird, really thought they would be each on a different shoulder like how it already is with two parrots, haven't tested with other pets that rest in your shoulder like capuccino monkey, so better test with them as well, might also be cool if the leather glove acted as a 3rd shoulder while we hold it, so eagles and pootoos could also become shoulder pets (maybe just eagles since pootoos aren't tameable)
sometimes crows stop following us in our shoulder and stay freezed in the air for a time, not sure

• Snow Leopard:

They attacked and killed my pet crows :( can they please not attack any of our pets at all? I heard snow leopards are naturally shy towards us, so would make sense for them to not be hostile towards us and anything with us, even run away from us.

• Emu:

Skeletons drive them to extinction, they aggro every skeleton on sight and they attack back, and since they don't always dodge projectiles they eventually die to skeletons, so this is quite stupid, maybe just make they able to dodge all projectiles, they won a war after all... and I do not want to have to illuminate every inch of my farm, maybe if they made some flower glow that would actually blend well...

• Toucan:

They don't fly... why don't they fly?!

• Leafcutter ants and anteaters

They're neat ambient additions for the game, but why do they even exist? Their only purpose is for that are two items, a very mid food item that can alternatively be used on... guess what... the same ants, this is like a capitalist typhoon game where you get money that can only be used to get even more money, and the pupae only serves as an alterantive for maggots and mosquito larva for 3 mobs, wow. Also anteates serve pretty much to get those same resources, and do a funny pose when attacked. I heard anteaters are pretty hostile so would make sense for them to do the pose whenever we get too close, before attacking.
Not to mention that leafcutter ants actually destroy leaves and make forests look like herobrine has been there, please just make it stop.
Quick idea for anteaters, but what if their attack could break/penetrate armor in some way, and when digging anthills they can drop their claws that can be used for some weapon that's great against armored enemies? that still seems better than everything the leafcutter ants offer, seriously spawn and ice & fire did way better ant mobs.

Features that should be a thing, if not already:

• Do frogs eat the small bugs from the mod? like flies and cockroaches, that would make sense, but i don't think stupid mojang made them able to eat the vanilla small bugs like silverfish and endermites anyway, can't think of a benefit for them eating them, but maybe they could be bottled and directly fed to the frogs to breed them instead of slime balls? that would be very neat.
  Also can frogs transform into warped toads in anyway?

• Animal drops should be integrated in loot as an alternative besides killing them, like kangaroo and crocodile hide, some ideas i have are those hides replacing leather in fishing loot in the mobs' respective biomes (swamps and badlands, for example), besides them being part of the loot table from the structures in their respective biomes, like kangaroo hide and emu feathers in dungeon temples, and maybe even compatibility with modded structures.

Other ideas i have:

• Sunbird feathers
  Since its based on ho-oh from pokemon i thought it would be neat to add more to it than just a rare occurance that can give a blessing
  A feather always gets dropped right above the player when the bird spawns, then more can occasionally drop while it flies, feathers can also be found in jungle temples.
  What are they used for? don't really got much ideas, besides a potion that let you fly with elytra without losing height, or still give some sort of boost to elytra, a totem that summons the bird at will (that can also be found in jungle temples) and maybe a fan that blows gusts of winds that can push entities away or the player itself if used against a block, useful for gaining an elytra boost, i think there was a similar fan in the twilight forest mod...