About half of the 80,000 barnacle geese, which breed in Greenland, arrive on Islay for the winter, with further flocks wintering on other Scottish islands (e.g. Uists, Tiree, Colonsay) and many thousands wintering in Ireland. Tens of thousands of pink-footed geese use the Montrose Basin as a winter roost in October and November as they do Loch Strathbeg and various lochs and reservoirs in Tayside and the Lothians. The amber-listed black and red-throated diver's freshwater breeding strongholds in the British Isles are in the north and west of Scotland.