There’s a reason ducks don’t all dress the same
Not all mallard drakes exhibit the colours that are evident on the duck on the right. There’s an interesting reason for this.
Mallards were introduced into New Zealand more than 100 years ago.
Acclimatisation societies bred from these and released some 30,000 mallard ducks hroughout the country.
By 1974 the mallard had become the most numerous waterfowl in New Zealand and there were many cases of interbreeding with the native grey duck and, in some instances, with domestic ducks.
As a result of this hybridisation the plumage of many mallards became very variable and the drakes, especially in the breeding season, lost much of their distinctive colouring.
With its glossy green head and brown breast, the drake in this photograph is more like the original imports.
Like the grey duck, mallards live in wet lands where they eat water plants and all sorts of small aquatic animals.
They have an average life expectancy of three years but in favourable conditions, can live for much longer, some to 20 years.
It’s interesting to note that as a general rule birds in colder climates tend to be larger and heavier than related ones in warmer climates.
This feature is known as Bergmann’s rule which states that the heavier body tends to prevent heat loss.
Mallards in Otago and Southland are said to be stockier than the same species in warmer areas near the equator.
About 500,000 mallards are shot each year by enthusiastic hunters.