Threats to Chatham Island oystercatcher
Chatham Island oystercatcher nest
containing eggs, Tioriori Beach,
Chatham Island
Predation of eggs and chicks by cats, hedgehogs and weka has a major impact on species productivity and has been the most significant cause of population decline.
Domestic stock are known to crush eggs and chicks. Vehicles driven on the beach also pose a threat to nests.
Introduced marram grass has formed dense swards along much of the coast and artificially steepened the sand dunes, leaving few open areas the oystercatchers prefer to nest in. This forces the oystercatchers to nest close to the high-tide line where tides and storm waves can wash away nests.