One of the driving forces behind shifting and growing wings is the need, not want, to be in the wild, the sea, or the sky - We call these the Calls.
Almost all nonhumans experience these calls, they are universal. If you do not feel any of these calls, then you are very very likely human. The calls are not choices. These are not wants. These are not mental shifts - they are instinct, they are what drive shifting. You cannot force one of these calls to appear. You cannot force a call to go away - they are as permanent as death. They are more than otherkinity and more than therianthropy. They are eternal, the phone that rings even in sleep.

The first and largest call is the call to the wild. Many nonhumans have this call, from wolf shifters, to dragons, to extra limb growers. The call to the wild is the pull, the need, not want, to be in the wilderness living freely. But even that is an understatement. It is a phone that never stops ringing, a hook that never stops being tempting. When you look out the car window and your entire body wants to run off into the woods for no reason other than you need to be there, you need to be out there, that is the call to wild, and it can also be applied to the other calls.

The second call is the call to the sea. Mermaids, ocean dragons, marine shifters, they all experience this call. Similar to the call of the wild, it is the need to be in the ocean or water, to return to the ocean, as it is their home.

The last call is the call to the sky, another large call that is experienced by avians, dragons, and other winged creature shifters. This call is not to the wild or to the sea, this call is for the air. The nonhumans who have to fly - without it they will never be complete. Without flight, these nonhumans feel their life isn't worth living - they need to fly.

This is what separates humans from nonhumans - You have likely noticed that those growing wings for aesthetics or wants never go through with it fully - yet those who feel like they need to fly to feel complete or at ease with themselves, always do. The same thing goes across all types of nonhuman - those who try shifting or growing wings, but later give up or stop, they realized they could live without it - they were not meant to be nonhuman.

After all, why shift if you do not feel the call? For what purpose are you shifting? A fantasy? A dream? Why do people give up on shifting/growing wings? Because they realise they can live without it. Shifters/avians cannot live without it. The call, the need to shift or grow wings, it is present in all shifters/avians from birth. And every single nonhuman is meant to be nonhuman, therefore they already are nonhuman, and they always have been nonhuman. no subliminal, no spell, nothing can change that.

We can also separate the calls into further subtypes - ie, the call to the river, the call to the tropics, or the call to the mountains, however this isn't always necessary. It can help to separate when you are finding out your explicit nonhuman type or species, but there are still three main categories.

Naturally, there are some types of nonhumans and additive types that will not feel the call, such as blood vampirism or many yokai (as yokai can be nonphysical nonhumans and physical, and kitsune seem to not feel the calls, however nekomata, bakeneko, raiju, and many others do.)

All shifters follow the laws of physics - Mass cannot be created nor destroyed - meaning even a fox shifter would become a human sized fox, which also causes issues when finding your explicit type.

The most common shifters are, naturally, mammals. Wolf shifters, big cat shifters, other canidae and felidae shifters, ursidae and ungulate shifters, almost every mammal type has a shifter - and these shifts are often seen as "easier" to occur, as mammals are relatively similar to human forms. Due to the large variety of mammals, many terrestrial mammal shifters confuse their calls with wolves.

Merfolk and marine mammal shifters are slightly rarer, with nonmammalian marine shifters being even rarer. Many mermaids may be confusing their call to the sea with being a mermaid as opposed to being a dolphin shifter or seal shifter, or for nonmammalians, a shark or octopus (Yes octopi shifters exist, it's quite terrifying).

Draconics and mythics also popular shifters - yet are rare. Many people will conflate dual or triple calls to being a dragon, when there are many mythical creatures one could be - ie, a gryphon, peryton, manticore, etc. Dragons and many flying mythic shifters experience two to all three of the calls, depending on their breed (dragons) or habitat.

And last, Avians. Quite popular, I would say, but there is a missing link - How many avians are actually bird shifters, confusing the need to fly with the need to grow permanent wings? I can only imagine many. Bird shifters are heavily scrutinized, many believe they do not exist - However, they do. Biologically observed limits of powered flight cap out at the Argentavis, who is well within human sized. Another nitpick at bird shifters existence is with feathers - dead cells, how could they shift back? Well, wolves can shift triple coats of fur, also dead cells, so this point is moot from it's beginning.

Nonmammalian shifters, ie reptiles, fish, etc. are very rare and have many dangers - reptiles require specific temperatures to perform bodily functions, an anaconda shifter in the Midwest would not last long. These shifters also often have the hardest time shifting, or so I've heard as I have never met one.

Understanding the wide variety of what the calls apply to, and finding your exact type takes a lot of introspection - do not settle for one thing because it's popular - explore all possibilities, even if this leads to the often-mocking title of a "species jumper", finding who you are should be the priority.