THE myna bird is proving a major problem for native birds, with research showing the introduced species is squeezing out some of Australia's signature species including the laughing kookaburra, crimson rosella and sulphur-crested cockatoo.
Research by the Invasive Animals Co-operative Research Centre and the Australian National University found many native species come off second best when competing with the common myna bird for nesting sites and food.
Using 29 years' worth of data collected by the Canberra Ornithologists Group, the research measured the abundance and distribution of 20 bird species in Canberra. The data covers survey areas prior to the arrival of the myna, introduced to Canberra between 1968 and 1971. While it remained localised, the bird has now spread throughout the city and there are more than 93,000 of them.
Published in the journal PLoS One, the results show that even when taking into account the capital's urbanisation, the myna's arrival has reduced numbers of cavity-nesting birds such as the sulphur-crested cockatoo, crimson rosella and laughing kookaburra. Numbers of the crimson rosella have fallen from about 5.9 per square kilometre to 2.4 per square kilometre a year, while numbers of the sulphur-crested cockatoo have fallen by 2.0 per square kilometre and the laughing kookaburra by about 0.4 birds per square kilometre.
Eight smaller species including the grey fantail, magpie-lark, willie wagtail and silvereye also fared poorly.
''We've clearly got negative relationships between some birds and the myna,'' said lead author and PhD candidate Kate Grarock. ''Although our study focused on the city of Canberra, it is likely that similar interactions may be occurring in other Australian cities.''
The findings are notable, as change in species abundance is often slow and gradual.
However, not all native birds fared badly since the myna's arrival. Some populations have apparently increased since its arrival, including the galah, eastern rosella and Australian king parrot.
Common myna birds, native to India, central and southern Asia, were first introduced into Australia in 1862 to control insects in Melbourne's market gardens.
The mynas' aggressive nature gave them an advantage when competing for nesting sites, food and territory.
The bird has been introduced all over the world and has become established on all continents, except Antarctica.