If you feel non-human and/or am trying to find your species identity, this is a guide that I hope will help. Please reply to the threat to give feedback or ask for help.
My technique involves a methodical process that will take time and patience. But the species you find, you can be pretty sure will be you. This method uses taxonomic classification charts to narrow down potential orders, genuses, and finally species, looking at characteristics of each as we narrow down. It is normal to explore more than one route or species/genus at once. We start off by looking at each class of vertebrate: Aves, Mammalia, Reptilia, Amphibia, Agnatha (jawless fishes), Class Chondrichthyes (cartilaginous fishes), Class Osteichthyes (bony fishes). Remember that some species, such as sharks, will be included in one of the fish classes.
We look at the species in each class and narrow down the orders, genus' and finally the species that you are. We'll look into appearance (though be careful not to put too much emphasis on this), behaviour, mannerisms, temperament, vocalisations, etc until you feel sure about what your species is. Its a good idea to keep options open at first, start with orders and work your way down each level of classification. Don't forget that it's fine to go down multiple routes at once if they seem like possibilities.
When you look into a particular species, research the behaviour, mannerisms, temperament, vocalisations, typical personality, etc of the species by looking around at reliable sources on the internet. (Wikipedia was only used as a guide for finding species). You will not be a 100% match with the personality, as everyone is an individual including animals. Try looking into how you behave and feel both now and when you were younger, even as a child, to get a good idea of what you might be.
When you find your species and have looked properly into it, you'll know it is part of who you are. There's nothing quite like it in my experience.
Don't be afraid to reply to the thread if you get stuck, unsure, or want to celebrate a breakthrough (however big or small). Also if you are new and strugglign with species dysphoria, feel free to vent here too.
Some sources to get started:
(Note: corvids are passerines)
(Fun Fact: birds are a type of theropod dinosaur)