 However, the events of World War II led to the complete loss of quail lines bred for their song type, as well as almost all of those bred for egg production.After the war, the few quails left were used to rebuild the industry, and all current commercial and laboratory lines today are considered to have originated from this population of quails.The Japanese quail is considered to be a closely related allopatric species to the common quail, though both are still recognized as distinct species.