Duck Research Milestone Reached
Fish & Game’s landmark mallard research project has finished its first season, and while there are another two seasons of research still to be completed, interesting preliminary data is already emerging.
The mallard project is a significant research effort by Fish & Game and follows concerns voiced by hunters throughout the country that mallard populations had fallen from levels seen in previous years.
Because the mallard duck is the mainstay of most New Zealand waterfowl hunting, Fish & Game is now trying to determine what the species requires to sustain a good, stable and huntable population.
The research team is looking at mallards in both the North and South Islands, focussing on Waikato and Southland because of those regions’ reputation as prime mallard hunting areas.
The researchers are trying to understand mallard productivity and habitat use and the initial results are interesting.
Using high-tech transmitters and tracking equipment, the team discovered that mallards began nesting in mid-July and by September, broods had started hatching.
Research technician Julie Unfried tracking ducks fitted with transmitters.
By December, most birds had finished nesting, although a few late broods were being hatched and reared through Christmas and into the New Year.
There was a difference in survival rates between the two regions.
In Waikato, nest survival appears to be around 50 percent, with some birds attempting to nest up to four times.
While nest survival appears higher than expected, duckling survival is in contrast, extremely low. Many Waikato birds hatched their first nest only to lose the entire brood within the first week.
Although most females which lost broods re-nested and raised a few ducklings the second time around, only 14 percent duckling survival was observed in Waikato.
This contrasts sharply with the results obtained in Southland. There, many birds successfully raised their ducklings on their first nest attempt, and while there was still significant predation on females, nest and duckling survival appears to be much higher.
Preliminary analysis suggests Southland’s nest and duckling survival may be as high as 60 or 70 percent.
From the information obtained during the 2014 breeding season, it would appear predators are to blame for the majority of nest losses.
One of the reasons for this is that the habitats the birds nest in, such as hedgerows and ditches, create an easy target for mammalian predators. Scientists describe such sites as being “lineal habitats” because they are in straight lines.
An unexpectedly high number of females were killed during incubation while on their nests. Initial observations suggest cats, stoats and hawks may have an important impact on female mallard survival during breeding. Pukekoes also took a toll on nests and ducklings.
The mallard research project is now a third of the way through its three year timetable and team members describe the first year as “an enormous success.”
Figures are now being analysed to provide the detailed picture required before conclusions can be drawn, and over the next two breeding years, more data will be collected in an effort to gain a comprehensive understanding of what the mallard population is doing in New Zealand.
Come spring 2015, the researchers and volunteers will be back out in the field gathering the huge volume of information and data necessary if meaningful results are to be obtained.
February 18, 2015