Three mallard ducks have been euthanised by the Department of Conservation (DOC) after they were observed preying on newly hatched pūteketeke (Australasian crested grebe) chicks in the Mackenzie Basin of Canterbury.
Unusual Predatory Behavior
DOC rangers responded to photos submitted by a member of the public showing the ducks actively hunting and killing the chicks near Lake Alexandrina, south of Lake Tekapo. Principal biodiversity ranger Dean Nelson described the behavior as shocking, noting that mallard ducks typically consume plant material supplemented with insects and snails.
According to Nelson, the ducks were “actively scoping out the pūteketeke nests to see if they had chicks.” The adult pūteketeke did not appear to recognize the ducks as a threat. This unusual predatory behavior is concerning to DOC experts, who fear it could spread as ducks are known to learn from one another.
A Precedent in Romania
DOC referenced a 2017 research paper from a Cambridge University scientist detailing a similar incident in Romania, where mallard ducks attacked and consumed the chicks of two common bird species. The research suggested the ducks may have been seeking a protein source prior to nesting.
DOC staff used nets to capture the three ducks and then humanely euthanised them. Further checks were planned for Wednesday to determine if other mallard ducks were exhibiting the same behavior.
The pūteketeke is classified as a nationally vulnerable bird, and a colony of 40 to 50 nests has been established annually for the past five breeding seasons in the area. Campers and boaties were asked to be vigilant around Lake Benmore last December following reports of disturbed nests.
Frequently Asked Questions
What prompted DOC to euthanise the ducks?
DOC euthanised the three mallard ducks after they were observed hunting and killing pūteketeke chicks, a behavior considered unusual and potentially harmful to the vulnerable bird population.
Are pūteketeke native to New Zealand?
Despite some misconceptions due to their name, pūteketeke are native to New Zealand and are currently classified as nationally vulnerable.
How can the public help DOC monitor wildlife?
DOC encourages the public to be engaged with nature and report any concerning wildlife behavior, such as disturbed nests or unusual predatory activity, providing photos as evidence when possible.
Given the unusual nature of this incident and the potential for learned behavior among ducks, what further steps might DOC take to protect pūteketeke chicks in the future?
