Male Japanese quail have relatively large testes (2.26% of body weight), a rapid rate of spermatogenesis (14.4-15.8 days) and an efficient production of spermatozoa (92.5 x 10(6)/g testis per day). The daily output of spermatozoa is high (308 x 10(6) per bird, 2.08 x 10(6) per g body weight). The total number of extragonadal spermatozoa was 308 x 22 x 10(6) per bird. Spermatozoa were transported through the genital ducts in about 1 day, maturing quickly in the epididymal region and stored briefly in the ductus deferens. Spermatozoa isolated in the ductus deferens by ligatures around the duct rapidly lost the capacity for motility after 3 days. It is concluded that, compared to mammals such as the rat, the reproductive strategy of the quail involves the rapid production, maturation and transport of spermatozoa through the reproductive tract, in association with a limited capacity to store spermatozoa for long periods within the male genital ducts.