sentences:  There are 19th century reports of shore plovers from the South Island and several parts of the North Island, but by the 1870s they had vanished from the mainland, surviving only on the Chatham Islands.Introduced predators such as feral cats and Norway rats were the main culprits.Shore plovers (unusually for shorebirds) nest under cover (such as driftwood and vegetation) or in burrows under boulders.