It was not easy leaving the baby bird with the turtle, but you definitely managed to do it. It must have been the most difficult decision you have ever made while simultaneously being the easiest action you have ever performed.
It also does not make you terrible.
Did you abandon a helpless creature, leaving it with the most boring and oddly anti-bird turtle to ever exist?
Did you go through a tremendous amount of work only to have it soured by a long, drawn-out story?
But you are just a bear. A bear that abandons helpless animals.
As long as you can live with it, everything should be just fine.