Hallig Habel (Danish: Habel, North Frisian: Haabel) is the smallest Hallig in the German Wadden Sea, and is a bird sanctuary. It is administered by the Gröde municipality on the neighbouring island. The surface area of Habel measures 7.4 hectares with about 655 metres in length, and 100 metres width. On this island there is an artificial dwelling hill called Norderwarft with a house that hosts an ornithological observatory during the summertime. A second hill on the southern shore, Süderwarft, was abandoned in the 19th century and was then destroyed by the sea.