nearly four hundred species of bird have been recorded in the country. many of them are resident species but others are migratory and just passing through, while still others overwinter in turkmenistan. some of these are the ducks, geese, and swans that inhabit the shores of the caspian at this time of year. the largest lake in the country is sarygamysh lake, on the border with uzbekistan; this is now a nature reserve and attracts wildfowl including pelicans, coots and cormorants. yeroylanduz is a natural depression which floods each year and attracts pelicans, flamingoes and other birds.