So-called predator ducks have shocked conservation staff in the Mackenzie Basin

Department of Conservation rangers in Twizel were alarmed when a member of the public alerted them to mallard ducks hunting and killing puteketeke chicks next to Lake Alexandrina.

Principal Biodiversity Ranger Dean Nelson says mallards are not known to prey on other birds, normally feeding on plants with small amounts of protein from insects and snails.

Three ducks involved have been captured and humanely euthanised, with DOC urging the public to report any further incidents.