Saturday, 25 October 2014

Noisy Miners

Two Noisy Miners - a pest or a successful adaptable species?
As a woodland species that favours clear ground with not much shrubbery, Noisy Miners Manorina melanocephala have adapted well to the human-cleared woodlands around Canberra. They nest in loose colonies with their nests about a hundred metres apart, and as they as very demonstrative against intruders they fit their name. Although we can tolerate their mobbing and chasing, smaller birds can't and many parts of the woods which hold Noisy Miners lack some of the usually more common bird species.

A typical clutch of three Noisy Miner eggs lying on a lining of kangaroo hair
A secondary factor which also helps the miners dominate parts the woodland is the grazing of the understorey and grasses by Eastern Grey Kangaroos Macropus giganteus. These large herbivores have grazed the ground cover down to very short swards and bare ground in some places. And in the absence of a predator, the kangaroos numbers are abnormally high. The local authorities do cull some animals but the population was allowed to build up to such a high level previous to this that it will take many years before the vegetation is restored to a more balanced composition of ground cover and shrubbery, which in turn will support a wider range of animal life including those missing species of birds.

But the Noisy Miners are happy and they further benefit from the kangaroos by using their cast fur as a lining for their nests. So, can these two species be regarded as pest native species, due to their abundance and effect on the woodlands and other bird species, or are they simply successful adaptable species that can thrive in a human-created landscape.

A group of Eastern Grey Kangaroos in Canberra woodland with little understorey

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