Species
There are three main species of white corella found in the central and northern Wheatbelt, these are the Western Corella, the Little Corella and the Long-Billed Corella. All three of these species are declared pests under the Biosecurity and Agriculture Management Act 2019 (BAM Act 2019). A fourth species, the Muir’s Corella, is found in the southern Wheatbelt and further south around Tone Bridge, Rocky Gully, Frankland River and Lake Muir area. This species is also a declared pest.
Why do they need management?
Human activity has enabled corellas to breed in large numbers, well above what would have been possible prior to European settlement. Consequently, the birds cause negative environmental, social, and economic impacts.
Environmental Impacts
Descending in large numbers, corellas will strip trees of their leaves. They can turn a healthy tree into a stag, with no leaves on its upper branches through their chewing and breaking off branchlets. In the Wheatbelt, where mature native trees are scarce, this can have a devastating environmental impact. Corellas compete with endangered black cockatoo species and other native cockatoo species such as the Major Mitchell for nesting hollows. Corella’s have been reported removing eggs and hatchlings of black cockatoos from the hollows so that they can take over the nest.
Social Impacts
When congregating in large numbers, corellas make a large amount of noise when attracted to feeding sits and congregating at roost sites disturbing the tranquillity within an area. The droppings can foul trees, washing on clothes lines, buildings and recreational areas.
Economic Impacts
Corellas have a varied diet and are naturally very curious, traits that often result damage to public and private amenities. They chew through power lines, damage vehicles, shops and housing with their powerful beaks. They can often be seen on sporting fields or large areas of grass where they will pull up and damage both synthetic and natural turf. They damage crops, grain storage facilities and foul water bodies. Corellas have even been cited as having a negative impact on local tourism.