BACKGROUND
History
The rainbow lorikeet Trichoglossus haematodus moluccanus was first recorded
in Perth in 1968 and the population was thought to have originated from
fewer than 10 birds that were either deliberately released or had escaped
from aviaries. Since the early 1960s, the population has increased
exponentially and is spreading rapidly over the metropolitan area.
Distribution
The rainbow lorikeet occurs in south and east Indonesia, east through New
Guinea, the Solomon Islands, Vanuatu, New Caledonia and the north and east
of Australia (Figure 1, Higgins 1999). In Australia, the rainbow lorikeet
occurs from northern Queensland and along the east coast to Eyre Peninsula
in South Australia and a feral population occurs in Perth (Figure 1; Higgins
1999).
Figure 1. Distribution of the rainbow lorikeet species complex Trichoglossus
haematodus (modified from Barrett et al. 2002; Forshaw 2002).
Status
Under legislation administered by the Department of Environment and
Conservation (DEC), rainbow lorikeets are recognised as Acclimatised Fauna
in the south-west land division. This recognises that lorikeets are native
birds living in the wild as a result of being released, escaping or being
the offspring of released or escaped birds. The Acclimatised Fauna Notice
states that lorikeets can be taken on private land in the south-west land
division, without the need for a Damage Licence from DEC. The notice
stipulates that a person taking lorikeets must not damage trees and may only
use a trap if licensed to do so under DEC legislation.
Under legislation administered by the Department of Agriculture and Food
(DAFWA), rainbow lorikeets are declared pests in Western Australia, in all
areas south of the Kimberley including the Perth metropolitan area. This
means that private, municipal and State government landholders are
responsible for control of lorikeets on their land.
Impact
The Rainbow Lorikeet Working Group (see below) has overseen the production
of a comprehensive review entitled The Status and Impact of the Rainbow
Lorikeet
(Trichoglossus haematodus moluccanus) in South-West Western Australia
(Chapman 2005)
(http://www.agric.wa.gov.au/content/pw/vp/bird/lorikeetmiscpub.pdf).
Chapman (2005) collated information showing that rainbow lorikeets are a
serious pest of cherries, apples, pears and stone fruit and a very serious
pest of grapes elsewhere in Australia. A pest risk assessment conducted by
DAFWA predicted that the feral rainbow lorikeet population in Perth posed an
extreme risk to the State's social, environmental and agricultural values.
In the Perth region, rainbow lorikeets cause a variety of problems
including:
damage to commercial and backyard fruit crops;
fouling of outdoor areas and vehicles with
droppings;
competition with native species for food and nest
sites; and
noise.
In the Swan Valley, rainbow lorikeets damage commercial table and wine grape
crops and they have also been reported damaging fruit in orchards in the
Perth hills.
These lorikeets also pose a potential disease risk to wild and captive
parrots because they are carriers of Psittacine beak and feather disease. It
is possible that they will also have a negative affect on hollow-nesting
species including the Purple-crowned Lorikeet, Elegant Parrot, Ring-necked
Parrot, Red-capped Parrot, Western Rosella Honey Possum and Pygmy Possum.
Potential Distribution
Bioclimatic modeling, together with an assessment of habitat and
agricultural production predicted that rainbow lorikeets could most readily
establish in the south-western sub-districts of Menzies, Warren and Drummond
(Lamont 1996, 1997). Within these sub-districts, suitable areas for the
establishment of the lorikeets included Bunbury, Nannup, Manjimup, Frankland
and Albany (Lamont 1996, 1997). Other modeling by the Department of
Agriculture and Food concludes that lorikeets will be able to establish in
many parts of the south-west (Figure 2).
Figure 2. Map showing the similarity in climate between the rainbow
lorikeet's overseas distribution and Australia; the pink and green areas are
where there is a high degree of overlap (generated by W. Kirkpatrick using
CLIMATE).
Rainbow lorikeets have already been recorded outside the Perth metropolitan
area at Esperance, Mandurah (Birds Australia unpubl. data), Coolgardie
(Chapman and Hazelden 1994), Boddington, Boyup Brook, Bunbury, Carnamah,
Katanning, Williams, Geraldton, Bailingup, Bridgetown and on Rottnest Island
(Department of Agriculture and Food unpublished). These incursions resulted
either from migration from the metropolitan population or from escapes or
releases of captive birds (Department of Agriculture and Food unpublished,
Department of Environment and Conservation unpublished) and show that the
lorikeets could potentially colonize the regional areas of Western
Australia.
Managing the Size of the Population
Modeling was recently carried out by the Department of Environment and
Conservation using the VORTEX (Lacy et al. 2005) model. Based on an
estimated starting population of 15 000 birds, the indications are that if
4000 to 5000 lorikeets were removed from the Perth population each year for
the next 5 to 7 years, with follow-up maintenance of 500 - 1,000 birds per
annum after this period, the population could be kept at a low level of less
than 1,000 birds.
Rainbow Lorikeet Working Group
In the mid 1990s, amid growing public concern about the impact of lorikeets,
Lamont (1996) called for: research and monitoring into the ecology and range
extension of the lorikeets; assessment of the impacts of the lorikeets in
the south-west; and the development of effective control measures.
In response to concern from community conservation groups and the general
public, the Rainbow Lorikeet Working Group WA was established in February
2004. The working group consists of representatives from the Agriculture
Protection Board (chair), the Department of Environment and Conservation
(DEC), the Department of Agriculture and Food (DAFWA), the Western
Australian Museum, a former member of State parliament, the Department of
Local Government and Regional Development, Birds Australia Western
Australia, the Westralia Airports Corporation, the United Bird Societies of
WA, the WA Fruit Growers Association, City of Swan, Wine Industry
Association and the Grape Growers Association.
The purpose of the Working Group is to formulate aims and objectives to
manage the rainbow lorikeet population in south-west Western Australia.
Management Strategy
The Rainbow Lorikeet Working Group WA requested the preparation of a report
Chapman (2005) to:
summarise what is known about the rainbow lorikeet
for reference by the working group;
examine the status and management of the lorikeet in
other regions;
assess the threats posed by the feral population in
south-west Western Australia; and
formulate the aims and objectives for an integrated
pest management program.
The report concluded that an integrated pest management program must be
developed to:
restrict the population to the Perth metropolitan area, and reduce the
number of birds in the population.
At the time the report was produced, based on a population model, the number
of birds in the papulation was estimated at 10,000, but subsequent roost
counts and modelling have estimated the population to number possibly
15,000.
The report indicated that a management program or strategy should include
the following objectives:
1. Investigate sources and obtain the funding required to manage the
population.
2. Estimate the number of birds in the Perth population, establish its
distribution and locate major roost sites.
3. Alter the status of the rainbow lorikeet in south-west Western Australia
so that it is a declared pest in the metropolitan area (alter to A2;
'subject to eradication in the wild' south of the 20th parallel of latitude,
and A5; 'numbers to be reduced/controlled' in the Perth metropolitan area).
4. Investigate methods of population reduction in the metropolitan area and
document their effectiveness.
5. Educate the public on the impacts of rainbow lorikeets and the need for
control.
6. Eradicate rainbow lorikeets that are sighted outside the metropolitan
area.
7. Investigate and document the effectiveness of methods for the mitigation
of agricultural damage.
8. Conduct a cost/benefit analysis of the damage caused by rainbow lorikeets
and lorikeet control.
9. Develop a molecular approach to population control and management.
10. Review standards for the import and keeping of rainbow lorikeets to
reduce the risk of aviary escapes.
Since the report was published in 2005, the Rainbow Lorikeet Working Group
WA has formulated a number of actions that are needed to meet each of the
objectives. It has commenced or completed many of the actions. For those
actions that are yet to be completed, the Working Group identified the means
of achieving these.
End.
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