i used to have a burial for every dead animal i came across. my mom would find a suitably sized box and i, followed by my brother and mother, would make a procession to the yard where either my mom or brother would dig the hole. i would say some solemn words to send the creature off and that was that. i always felt better knowing i had done some ceremony for the little bird or mouse because it seemed too sad to just leave it out there, dead.