It seems that there was no code created to differentiate jumping and entering/exiting boats. When you enter a boat, the game seems to treat it as if you were jumping and dismounts the parrot from your shoulder.

What I expected to happen was...:
The parrot would stay on my shoulder while I entered a boat.

What actually happened was...:
The game instead treated it as if I were jumping and dismounted the parrot

Steps to Reproduce:
1. Tame a parrot, then put in on your shoulder.
2. Get in a boat. Be careful not to fall or jump.
3. The parrot will dismount.