Dough Ray Me-ow (1948)

Louie the Parrot finds a written will stating that his master bequeathes the family fortune not to him, but to his fellow household pet, a lunkheaded cat named Heathcliff, with the proviso that Louie is next in line to inherit the wealth if Heathcliff dies. So, Louie plots the untimely demise of Heathcliff.