area of the oviduct between the uterus and vagina with tubules or grooves that can store a small number of sperm after insemination; released to move up the oviduct to the infundibulum to fertilize an ovum when triggered by hormones, perhaps also by passage of an egg down the oviduct; the amount of time sperm can be stored and remain viable in Bald Eagles is uncertain, but may be as long as 2 weeks; stored sperm may be less motile and thus less successful in fertilizing an egg than freshly inseminated sperm