案例背景："Opa", which means "the large owl" from the American Indian word, refer to history of Mississippi. It's a kind of nocturnal fierce bird of prey and the largest owl, with a full body length 80 cm and a weight of 1000-2200 g. Northern eagle owls often act alone except during the mating season. It takes rests in dense woods during daytime, however It has extremely good sense of hearing and visual ability during the night. And quickly dive to kill rats and small birds with its 4 centimeter long sharp claws and bill.