It’s roughly estimated that there are 4.5 million mallard ducks in New Zealand. Just like the human population of NZ, sometimes it feels like they are all in Auckland. Not true of course, but with ducks and humans having close to a 1:1 population ratio in NZ, it’s easy to speculate.
What is true however, is that the mallard is New Zealand’s most numerous and widely distributed waterfowl. Since its introduction in 1867, the mallard has colonised all of New Zealand and its distant islands. It has cross-bred extensively with the native grey duck, or pārera, resulting in the grey duck now well on the way to “extinction through hybridisation”. Pure grey ducks are now considered rare.
Some people feel the large urban populations of ducks are cause for concern, both from both a health and nuisance perspective, complaining they excrete on roofs and decks, get into gardens, wander inside homes, and harass their backyard chickens. Others feel it’s their duty to feed them as though they are incapable of achieving this natural feat unaided. But as with most human interactions with wildlife, it’s the wildlife that comes off second best.
Dr Lynn Miller, General Manager of NZ Bird Rescue in Green Bay, believes that the urban duck population is artificially high, and it’s to the detriment of the ducks.
“We’ve made the problem much worse by feeding them and encouraging them to stay and live as urban ducks,” Dr Miller said. “Not only that, but many also feed them white bread which is a cheap carbohydrate filler. It’s the equivalent of a McDonalds diet on crack”, she says.
She goes on to say that studies show birds cared for in people’s backyards tend to breed earlier, have larger babies and more of them “because they’re getting this artificial inflation of calories”. “The females also return to breed where they were hatched which they instinctively regard as a successful breeding area”.
And it’s not just the duck population that’s out of balance due to feeding by well-meaning public; other species such as sparrows, pigeons, mynas and rats also thrive on the leftovers.
Dr Miller warns that an overpopulation of birds increases the likelihood of infectious pathogens to crossover to other species, including cats, dogs, and humans, citing a salmonella outbreak among sparrows in 2002 in New Zealand which killed two people.
She urges people to encourage birds to forage naturally by not feeding them, but advises those who are involved in feeding birds to take care with their hygiene practices. Salmonella is passed on through the faecal-oral route, but is relatively easy to avoid by regularly washing hands and any equipment used to feed birds such as backyard chickens, with hot soapy water.
While some call for the ducks to be culled, Miller argues that the numbers in city areas can be reduced simply by reducing the feeding, the pay-off being that you enjoy the few birds that are around.”
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