an area greater than 15 hectares (approximately 37 acres). Records for the last date of settlement for the smaller uninhabited islands are incomplete, but all of the islands listed here would have been inhabited at some point during the Neolithic, Pictish or Norse periods. 'Ward Hill' or a variant thereof is very common as the name of the highest point on the island. These locations are named after those high places used for the lighting of warning beacons. The population of the tidal islet of Holm of Grimbister was not recorded by the 2001 census, although it was inhabited in 2010 and probably earlier. It did appear in the 2011 tables. The population of Inner Holm in 2001 was one, although the figure was included in the total for Mainland at the time of the 2001 census. Lamb Holm is "included in the NRS statistical geography for inhabited islands but had no usual residents at the time of either the 2001 or 2011 censuses". Papa Stronsay had usually resident population of 10 in 2001 but was apparently not permanently inhabited in 2011. Smaller islets and skerries This is a continuing list of uninhabited smaller Orkney islands (many of which are called "Holm" from the Old Norse holmr, meaning a small and rounded islet), tidal islets only separated at higher stages of the tide, or skerries which are only exposed at lower stages of the tide. In the vicinity of: Auskerry: Lunga Skerries, Oessen Skerry, The Clett. Calf of Eday: Lashy Skerries, The Bow. Cava: Barrel of Butter. Copinsay: Black Holm, Corn Holm, Horse of Copinsay, Scarf Skerry, Sow Skerry, Ward Holm. Eday: Green Holm, Red Holm, Rusk Holm. Egilsay: Kili Holm. Eynhallow: Sheep Skerry. Gairsay: Holm of Boray, Holm of Rendall, Little Seal Skerry, Skertours, Taing Skerry. Glimps Holm: Dulse Skerry, Glimpsholm Skerry. Graemsay: Middle Skerry, Skerry of Cletts, Sour Skerry, Sow Skerry. Hoy: Grassy Cletts, Inner Skerry, Middle Skerry, Old Man of Hoy, Outer Skerry, The Needle. Mainland: Bo Skerry, Bow Skerries, Braga, Brough of Bigging, Holm of Houton, Holm of Rendall, Iceland Skerry, Kirk Rocks, Little Skerry, Mirkady Point, Nevi Skerry, Outer Holm, Oyster Skerries, Puldrite Skerry, Quanterness Skerry, Scare Gun, Seal Skerry, Skaill Skerries, Skerries of Clestrain, Skerries of Coubister, Skerries of Lakequoy, Skerry of Work, Skerry of Yinstay, Smoogro Skerry, Thieves Holm, Whyabatten, Yesnaby Castle. Muckle Skerry: Clettack Skerry, Little Skerry, Louther Skerry. North Ronaldsay: Altars