Why careful management of berry-bearing shrubs will help save the scarlet robin

Damon Oliver, Senior Team Leader, Ecosystems and Threatened Species, NSW DPIE, Queanbeyan.

Many of our NSW Tablelands landscapes have been heavily modified since European settlement. In addition to the loss and fragmentation of native vegetation, many introduced plant species from other parts of the world have proliferated as part of this landscape transformation. In the Southern Tablelands and Monaro regions large woody exotic shrubs and trees such as hawthorn, cotoneaster and pyracantha have been planted and then spread by their seed over the last 150 years.

These woody shrubs and trees have colourful berries that native birds, like the beautiful threatened gang-gang cockatoo, like to eat. They also provide harbour for our smaller birds in landscapes where trees and shrubs are scarce, either naturally or from previous clearing.  So, what’s the problem, you might ask?

The problem with too many pied currawongs

The answer lies in the connection between the readily available berries as a food source and the increased number of pied currawongs (Strepera graculina), a large black and white crow-like native bird. Most locals would be familiar with currawongs due to their distinctive call and seasonal fluctuations in numbers.

As a result of the modification of our natural environments and the proliferation of exotic berry-bearing shrubs, the number of pied currawongs has greatly increased across their range. No more so than in the Capital Region and surrounds where huge flocks can be seen, especially during the colder months of the year. So, the next question you might ask is what’s wrong with more pied currawongs?

Unfortunately, pied currawongs are highly skilled predators of the nests of small native birds including the threatened scarlet robin. Where they were once relatively uncommon and far more seasonal in their movements – the numbers of currawongs have become so great that they are now posing a significant threat to the survival of some of our threatened woodland birds.

Detailed research from the NSW Northern Tablelands clearly demonstrated the high rate of predation by pied currawongs of the nests of small native birds – up to 90% of small cup-shaped nests were predated in one study! Both eggs and chicks are taken by these cunning hunters. Small threatened native bird species, already struggling with small population sizes, don’t stand much of a chance of successfully breeding when they are up against such a constant threat.

The solution – Save Our Scarlet Robin project is here to help

Thanks to funding from the NSW Environmental Trust, the Save Our Scarlet Robin project has started to tackle the problem of too many exotic berry-bearing trees and shrubs. Starting with roadsides in the Queanbeyan-Palerang Regional Council area, the plan is to remove these woody weeds and to replace them with native shrubs. Ideally, native trees and shrubs should be planted in advance of woody weed removal to avoid the total loss of vegetation cover that would leave little habitat for birds and other fauna. Over time, replacement native shrubs will provide protection and food for our native birds. Acacias (wattles), for example, are great habitat for small vulnerable birds and provide food from their flowers and seeds – a great natural food source for gang-gang cockatoos who love eating wattle seeds.

The key message for the community is to not plant any new exotic berry-bearing plants, remove them from gardens and farms and replace them with appropriate native plants to ultimately reduce over-abundant pied currawongs in our region and help our threatened native birds thrive again, less they face extinction.

Read about the threatened woodland birds of our region on the Local Land Services website: https://www.lls.nsw.gov.au/regions/south-east/key-projects/save-our-scarlet-robin

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