CHAPMAN, T. (2005)

The status and impact of the Rainbow lorikeet> (Trichoglossus haematodus moluccanus) in south-west Western Australia.

17 Seiten.
Department of Agriculture and Food, Western Australia, Perth. Report 04/2005.

Executive Summary:

Rainbow  lorikeets  Trichoglossus  haematodus  moluccanus  were  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 spread rapidly over 174 km2 of the metropolitan area.  The population now numbers an estimated 8,400 birds and is expanding in range at a rate of 0.7 km per year. Rainbow  lorikeets  are  highly  mobile,  have  generalised  feeding  and  breeding  requirements  and  can  quickly  adapt  to  exploit  new  feeding  and  breeding  resources.    They  have  taken  advantage  of  the  year-round  supply  of  native  and  exotic  food  plants  available  in  Australia’s  major  cities  and  are  expanding  in  number  and  distribution  in  Brisbane,  Sydney,  Melbourne,  Canberra, Adelaide and Perth. The rainbow lorikeet is regarded as either a pest of agriculture or an unwanted organism in New  Zealand,  the  Northern  Territory,  Queensland,  the  Australian  Capital  Territory,  Victoria,  Tasmania and South Australia.  It is also a major pest of agriculture in the Northern Territory, Queensland and the fruit growing regions of the Adelaide Hills in South Australia. Analyses  conducted  in  this  study  show  that  the  feral  rainbow  lorikeet  population  in  Perth  poses an extreme risk to the State’s social, environmental and agricultural values.  Rainbow lorikeets cause a nuisance in the form of noise, damage to backyard fruit crops and fouling of outdoor areas and vehicles with droppings.  The large roosting flock of over 1000 birds near Perth  domestic  airport  may  also  pose  a  risk  of  bird-strike  to  aircraft.    

The  lorikeets  also  exclude native birds from feeding resources and nesting sites, kill the nestlings of other bird species and carry Psittacine beak and feather disease in the liver (once infected), which they can spread to native lorikeets and parrots. Lorikeets are a serious pest of cherries, apples, pears and stone fruit and a very serious pest of grapes in Australia and this study showed that the potential for rainbow lorikeets to spread outside  the  Perth  metropolitan  area  is  high. Thus,  the  lorikeets  pose  an  extreme  threat  to  Western Australia’s $245 million fruit, nut and grape growing industry. 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  from  an  estimated  8400  in  2004  to  an  estimated  5000  by  2020. The  management  program  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.

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