The Wildlife Map of the Hebrides

5. Coll

The pools inland from the football pitch hold large numbers of mallard and teal in the winter, along with small numbers of whooper swans. About 300 eider winter offshore here, usually in one or two compact flocks. The cliffs in the soft conglomerate rock of Broad Bay (made from solidified shingle and sand) are being worn down more quickly than the harder rocks of the Lewisian gneiss, creating rounded cliffs and some extensive rocky platforms on the shore.