[2] Other names and variations include ウッナイト (utnay-to), meaning "rib river wetland" or "where small streams come together" and ウトナイトー (utnay-tō).

[3] Around the lake is a wide area of swampy wetland dotted with small ponds and bogs, all part of the Bibi River floodplain.

[7] Other birds recorded there include the Canada goose, the Oriental stork, the northern goshawk, the white-tailed eagle, Steller's sea eagle, the peregrine falcon, the red-crowned crane, the eastern marsh harrier, and the yellow-breasted bunting.

[3][7] The creation of the Lake Utonai Sanctuary began in May 1976 as an effort to protect habitat for the Okinawa woodpecker.

[4][7] In May 1979, Lake Utonai was selected as the location for the first bird sanctuary for the foundation in order to protect it from increased development in the area.

[4] The sanctuary protects 510 hectares (2.0 sq mi), including Lake Utonai and much of the surrounding area.