Controlling the rainbow lorikeet in Tasmania: is it too late?

ABSTRACT

Throughout the world, many parrot species have established wild populations outside their natural range through accidental escapes and deliberate releases from captivity. The Rainbow Lorikeet (Trichoglossus moluccanus), native to coastal northern and eastern continental Australia, has established viable populations in Western Australia and New Zealand from escaped or released pets and more recently have established in Tasmania. The Western Australian experience with introduced Rainbow Lorikeets, clearly shows that significant costs and impacts to agriculture, the environment and human amenities can be expected if this species is not controlled in the early stages of population increase, while in New Zealand, early intervention has proven successful in removing the species from the wild. This study examines sighting records of Rainbow Lorikeets in Tasmania which have gradually established over 20 years and we present a model to assist in determining likely population trajectories under various scenarios of control. Modelling indicates that the removal of 200 birds per year from each of the three Tasmanian sub-populations would decrease numbers to near-zero within 4.6 years. This demonstrates the opportunity to effectively control the Rainbow Lorikeet in Tasmania still exists and substantial damage to agriculture and impacts to conservation values can be avoided, resulting in significant cost savings to the Tasmanian community.

KEYWORDS:

• Invasive species
• parrots
• wildlife management
• conservation

Acknowledgements

The authors thank M. Blythman, J. Febey, R. Gaffney, N. Hamilton, M. Holdsworth, M. Newman, A. Polkanov, R. Pickering, D. Stojanovic, M. Webb and E. Woehler for providing information on rainbow lorikeets and their expertise in numerous ways. K. Jensz and T. Priestley assisted with the preparation of figures. Past and present Wildlife Operations staff are acknowledged for their contribution. We are grateful to the many bird observers who reported sightings and to the members of the public who feed wild birds and willingly assisted in trapping efforts to control rainbow lorikeets in Tasmania. The work was supported by Tasmania’s Department of Primary Industries, Parks, Water and Environment.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.