plants such as the giant sensitive plant (Mimosa pigra) and mission grass are threatening habitats. Invasive species such as feral water buffalo and cane toads are also causing problems. Birds The region features a wide variety of birdlife, with over one in three of Australia's species having been sighted in the region. In particular, the Alligator Rivers area is known for its rich collection of waterfowl such as magpie geese, ducks, herons, ibises, and spoonbills. The Alligators Rivers floodplains form a 383,000-ha IBA which it is estimated to support some five million waterbirds, including over 1% of the global population of 22 species, significant numbers of three near threatened species, with another 11 restricted-range or savanna-biome-restricted species. Aboriginal culture Aboriginal people have lived continuously in the Alligator Rivers region for 50,000 years. The region accordingly has a rich heritage with cave paintings and rock carvings common with over 1500 sites. Many Aboriginal artefacts have been found in old camping grounds in the region. The southern part of Kakadu contains a number of sites relating to Bula, a god associated with creation, and these sites are considered to be both sacred and dangerous to the aboriginal people because of this association. Also, art relating to contact with Makassan traders and Europeans is found there. At Ubirr Rock near Cahill's Crossing on the East Alligator River, some paintings dating from 20,000 years ago have figures throwing spears and wearing headdresses to first contact with European settlement. The Gagudju people live in the area between the East and South Alligator Rivers. They share responsibility for Kakadu National Park which lies within their country. Gunbalanya (formerly Oenpelli), a settlement in the area, is run by an Aboriginal council and is an important centre for arts and crafts. The Gagudju language is no longer widely spoken, but was common until the early 20th century. The Jawoyn people live in the South Alligator and South Mary regions, as well as around Katherine. The Jawoyn negotiated an agreement in 1993 for the Coronation Hill uranium mine where they would allow further exploration of the area in return for employment and training for the Jawoyn and a partnership arrangement. The Kunwinjku people live between the Liverpool River and the East Alligator River. Traditional beliefs remain important to the Kunwinjku with Ngalyod, the Rainbow Serpent, playing an important part in their art and traditions. The Kunwinjku have received royalties