Drone controversy highlights duck impact on crops and water quality

NZ Herald

14-05-2025

Whatever the legalities of the misunderstanding that occurred at the opening of the duck-hunting season, there is continuing confusion about desires, wants and needs.
Society needs, wants and desires … food, health and environmental quality.
Mallard ducks, the most common duck in New Zealand, are connected to all three.
Southland farmers have shown examples of ducks destroying significant areas of crops.
Southland's Federated Farmers president Jason Herrick's description, ' the skies are black and the paddocks are black with ducks,' is reminiscent of locusts and farm devastation.
Crops destroyed by pests are a sunk cost to the farmer (soil preparation and seed, for instance) and a cost in terms of replacement feed for animals (sourcing and buying the feed itself and the transport and feeding-out time and costs).
This increases the cost of anything produced by the animal – the meat, milk or wool.
Will the consumer pay the extra?
Or might the people saving ducks be prepared to cover the costs of duck depredation at the farm level?
Health is sometimes overlooked in the impact of ducks on water quality.
Ducks contain a remarkable number of bacteria.
Researchers in Germany reported in 2009 that mallard ducks are an important reservoir for zoonotic E. coli strains.
They were found to be 'a substantial non-point source, especially of strains capable of causing extraintestinal diseases'.
In 2011, researchers at ESR (NZ Crown Research Institute) reported that ducks produce the highest loadings of E. coli and enterococci per bird; Canada geese produce the highest loadings of Campylobacter spp. per bird.
Further work by ESR (a report to ECan in 2015) compared duck production of E. coli with that from dairy cows.
Each duck was calculated to produce 1.17x 10 to the 10 E. coli a day, in comparison with each cow producing 2.01 times 10 to the 9 – an order of magnitude lower.
In contrast, lambs produced 4.53 times 10 to the 11.
Many zeros are involved in these numbers, but the basic order of production per live bird or animal a day was lambs, sheep, ducks, dairy cows, black swans, gulls, and Canada geese.
This explains the findings from the Southland Client Report Template,, again provided by experts from ESR, that waterfowl are the main contributors to faecal contamination of waterways during base flow, but that in periods of heavy rain, ruminant sources increase.
In some areas, human effluent from overflowing septic tanks and sewerage systems has also been recorded.
People are always advised not to swim during and immediately after heavy rain because of debris and high-speed currents, as well as the likelihood of microbial contamination.
Fencing to keep animals from direct access to riparian areas of rivers has reduced the impact of dairy cows and cattle, but in flooding, overland flow can create contamination.
Contamination from birds is always present.
The third consideration is environmental quality.
The origin of the New Zealand mallard population was the importation of game farm mallards from England between 1870 and 1930, and two later imports of birds and eggs from a game farm in Connecticut, USA.
Mallards are not native.
The Acclimatisation Societies (now Fish & Game) released over 30,000 mallards throughout New Zealand before 1974.
The mallards were then (and are now) the most common waterfowl in the country and had hybridised with the native grey duck.
Grey ducks are now 'nationally vulnerable': they have been competitively excluded by mallards.
The drone flyers might well have as their defence that their aim was to prevent animal cruelty.
That is also the aim of the hunter and their dogs – a clean shot and retrieval. There is pride taken in both.
Like many introduced species, mallard ducks have no natural predators in New Zealand; no foxes, bears, or large cats, for instance, and though ferrets are active in some countries, New Zealand is trying to control them because of other issues, such as native birds.
Alternatives are poison or increased food prices.
They are out of control, and the duck equivalent of kryptonite has not been identified.
The spy-drone was not faster than a speeding bullet, as in the 1940s Superman radio show (Superman was also deemed to be more powerful than a locomotive, able to leap tall buildings in a single bound.…).
The question remains about its purpose.
Ducks are fun to feed (though councils request that one doesn't) and ducklings are delightful, but they are associated with negative factors in food, health and environment – and the cost of the negatives is not being factored into any equation.
The animal welfare issues of too many ducks vying for a limited feed source (starvation and disease) have also not been considered.