In birds, after natural mating or artificial insemination (AI), sperms are transported through cloaca or vagina at the utero-vaginal junction (UVJ) of oviduct. Only 1% of the deposited sperm passes through the selection process in the vagina to reach the UVJ. In the UVJ, sperm enter the tubular invagination of the surface epithelium of the mucosa collectively called ‘sperm storage tubules’ (SSTs) where they are stored for longer duration retaining their fertilising capacity. The storage capacity and duration varies from species to species. This enables the birds to produce fertile eggs continuously. Shortly before and during egg production, sperm residing in the SST upon release will ascend the oviduct to the site of fertilisation in the infundibulum. Within the SSTs, sperm motility is suppressed and is initiated at some stage before fertilisation. Restoration of sperm motility is necessary for the release of spermatozoa from the SSTs. The exact mechanism by which sperm are stored in these tubules and released has not been established and hence, this is the focus of this review.

This review focuses on some of the main features of sperm selection and storage in birds mainly on the basis of studies performed in poultry species, with emphasis on the initial selection of sperm at the female vagina level prior to migration towards the sperm storage tubules. Sperm originating from low-quality males or subjected to inappropriate in vitro storage conditions are rapidly discarded, resulting in impaired fertility in corresponding flocks. In the absence of accessible and appropriate technology for matching the ‘storing’ potential of sperm in the oviduct, conditions for prolonged sperm storage under a liquid (through the use of semen extenders) or a solid state (cryopreservation) have received only limited attention, despite their potential interest to facilitate male and female management in poultry flocks. Despite this, technology for short-term liquid storage is currently used in turkeys, guinea fowl and muscovy ducks and also in progress in chickens. In addition, technology for cryopreservation of avian semen has become available for some species (chicken, goose) to facilitate the management of genetic resources, including the preservation of rare and economically important breeds.