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Western Australia |
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The State of Western Australia covers an area of over 2,500,000 square kilometres
(about nine times the area of New Zealand).
The Red Collared Lorikeet (Trichoglossus haemotodus rubritorquis) inhabits the Kimberly
area to the north of West Australia, but has never extended its range down the west coast
into south-west Australia.The nearest natural range of the Rainbow Lorikeet (Trichoglossus
haemotodus moluccanus) is near to 1500 kilometres away in South Australia, but unlike the
Purple Crowned Lorikeet, it has never extended its range along the southern coast into the
south western corner of Australia.
Introduction of the Rainbow Lorikeet to Perth
Six Rainbow lorikeets were released from Rottnest Island in 1960 after permission to release them was refused. These birds appear to have reached the mainland coast about 100 km south of Perth, and there vanished. A second release of 11 Rainbow lorikeets was made by a gardener of the University of Western Australia in about 1966. Although there has been a contraction of the range in some years, the population is now estimated by David Lamont of CALM, Perth, to number 2700 at end 1998. This estimate is based on a lifetable which gives an average annual increase of 19% from the start population of 11 in 1966.
Data provided by a census in Kings Park in the centre of Perth (kept since 1927 and now maintained by Professor Harry Recher, Foundation Professor of Environmental Management, Edith Cowan University, Perth), shows an average annual increase of sightings in the park from 1986 to 1995 of 11%, with sightings declining 4% from 1993 to 1995. From these figures it is possible that the Rainbow Lorikeet has reached a maximum density in the area of Kings Park.
Present status of the Rainbow Lorikeet in Perth.
According to recent information from David Lamont and others, the population after some 33 years has not expanded beyond the mature urban areas around Perth. It appears that the majority (77%) of their food resource is from extensive urban plantings of flowering trees, particularly winter flowering Eucalypts not native to Western Australia, such as Eucalyptus caesia, E. maculata, E. citriodora, and E. cladocalyx all being cited as common food sources, in addition to local Eucalypts.
They have not succeeded in colonising the new suburbs, the food resource being not
adequate to support them.
While they do inhabit the edges of the bush where these are close to the older suburbs
and their food supply, they have not colonised the West Australian wet sclerophyll forest.
Professor Brian Collins, Dean of Science, Curtin University, Perth, is also of the opinion
that there appears to have been no impact of the lorikeets on native bush adjacent to
Perth.
David Lamont’s 1997 paper said that there had been no indication that the Rainbow
Lorikeet would become a pest of commercial crops such as apples and pears, but suggested
that they could be as they were close to an important fruit growing district. In recent
correspondence he confirms that although the range of the Rainbow Lorikeets has been
adjacent to that district for at least the last two years they have not moved into it.
The only mention of damage to fruit crops in the same 1997 paper was isolated reports
restricted to mulberries in an urban situation, but provided no further details.
A May 1999 request to the Vertebrates Pest office of the Agriculture Department of Western
Australia returned the information that no complaints about fruit damage have been made
about Rainbow Lorikeets by commercial or private growers.
(The same paper by D. Lamont also reported that Rainbow Lorikeets were quickly developing as the principle pest species of commercial orchards in South Australia with the suggestion that they were becoming a more significant pest there than starlings. This claim which was not referenced is dealt with in the accompanying investigation into crop damage in South Australia.)
Unlike the Red Collared Lorikeet, the introduced Rainbow Lorikeet is not protected under West Australian law. As no complaints have been made by commercial growers regarding Rainbow Lorikeets to the Vertebrates Pest office of the Agriculture Department of Western Australia, it has not been gazetted as a pest. (Under West Australian law, no animal may be gazetted as a pest until it has been demonstrated to be a threat to horticulture).
The range of the Rainbow Lorikeet population in Perth is restricted to the older suburbs, and the bush edges where these are adjacent to the older suburbs. It is now very common in Kings Park, a 400 hectare park in the centre of Perth, well planted with flowering Eucalyptus species native to Eastern Australia.
Competition with other Parrots
Throughout the Perth suburbs the Rainbow Lorikeet co-exists in mutual competition with a number of parrots both native to Western Australia and introduced, all of which have overlapping resource requirements of nest sites (suitable nest holes), and additionally of nectar and pollen in the case of the Purple Crowned Lorikeet:
Parrots:
Resource Overlap
1 Species Lorikeet Nectar, pollen,
nest sites (not common in urban areas)
11 Species other Parrot Nest sites
Reports published in HANZAB from David Lamont of CALM, Perth, cite fighting between Rainbow Lorikeets and Galahs over nest sites, eviction of Twenty-eight parrot nestlings by Rainbow Lorikeets, and conversely eviction of Rainbow Lorikeet nestlings by Twenty-eight parrots. The paper published in Eclectus 1997 by David Lamont also suggests that the aggressive behaviour of Rainbow Lorikeets may affect Twenty-eight Parrots, Kookaburras, Western Rosellas, and Purple Crowned Lorikeets, a smaller lorikeet with similar habits to Rainbow Lorikeets.
However elsewhere in the same report he says that the impact on native avifauna is nebulous, that the threat must remain conjecture until there is evidence to the contrary, and also that the Purple Crowned Lorikeet may have a competitive advantage over the Rainbow Lorikeet. However the Purple Crowned Lorikeet and the Western Rosella have never appeared in the Kings Park census, and other reports indicate that they are not common in the urban area. In recent correspondence, David Lamont confirms that there has been no noticeable change in status of the Purple Crowned Lorikeet, and makes no mention of the Western Rosella.
Also in recent correspondence, David Lamont reported that data from Birds Australia links decreasing populations of Australian Ringnecks to increasing populations of Rainbow Lorikeets, but gave no further details for this claim. This claim is not supported by evidence from Perth, the census in Kings Park showing that the Twenty-eight parrot has increased in numbers in recent years by approximately 400% from 1952 to 1995, as it has elsewhere in the Perth urban area according to Prof Recher.
Other reports state that Ringnecks compete (presumably successfully) with Rainbow
Lorikeets for nest sites (HANZAB), while the Twenty-eight parrot is considered to be
common, aggressive, and successful (Forshaw, AP 1981).
Galahs appeared first in Kings Park in 1989, when a fire burnt 45% of the 267 hectares of
native vegetation, although the two events may be unrelated. Prof Recher reports that this
parrot and the Corella which have been introduced to Western Australia, are now very
common in the Perth urban area, and makes no mention of any adverse competition from
Rainbow Lorikeets to these or any other species.
Competition with Honeyeaters
The Rainbow Lorikeet also co-exists throughout the Perth suburbs in mutual competition with a number of honeyeaters, which have overlapping resource requirements of food (nectar):
Honeyeaters:
Resource
Overlap
2 Species Wattlebird Nectar
1 Species Miner Bird Nectar
13 Species Honeyeater Nectar
David Lamont claimed in correspondence that the population of Honeyeaters has decreased
in Kings Park due to competition from the introduced Rainbow Lorikeets. However the census
reports from Kings Park kept since 1927 show the opposite (Recher 1997). Prof Recher
reports in correspondence that although the Rainbow Lorikeet has become very common in
Kings Park and throughout the rest of the urban area, that there has been no noticeable
conflict between the Rainbow Lorikeet and other nectar feeders, and that the Honeyeater
population in Kings Park has shown no real change since 1927, except for an increase in
some species, and a decline in one species probably due to aggression from a more numerous
honeyeater.
Specific figures (Recher 1997) are available for the following species all of which feed
primarily on nectar:
Brown Honeyeater (140mm)
The Kings Park census shows an increase in the population of the Brown Honeyeaters from nearly 400% between 1952 and 1995.
Singing Honeyeater (200mm)
The census shows an increase of 35% from 1986 to 1995 in the population of the Singing Honeyeater, but this has not been noted elsewhere in Perth, where it is uniformly abundant.
White-cheeked Honeyeater (170mm)
The census also reports a more recent increase in the count of White-cheeked Honeyeaters, but this may be localised.
Western Spinebill (150mm)
The census reports a general decline. Aggressive interactions between the Brown Honeyeater and the Western Spinebill have been noted as common in the park, and this may explain the decline of the Western Spinebill due to interference competition with the greatly increased population of the Brown Honeyeater (H Recher 91)
Red Wattle bird (350mm)
The Kings Park census shows no changes in the population of Red Wattle birds since 1952. Prof Recher also notes that there is no evidence of any change in the Perth urban population of Red Wattle birds.
Another authority on Honeyeaters, Professor Brian Collins, Dean of Science, Curtin University, Perth, noted no hard effects of the Rainbow Lorikeets on the Honeyeater population of Kings Park. Prof Rechers opinion is that the effect of the Rainbow Lorikeet on the avifauna of Perth is neutral.
Competition with other Species
The Kings Park census shows that the population of Kookaburras has remained relatively constant since 1952. David Lamont reported one instance where evicted bats had been found under a tree on a golf course with beak marks possibly made by Rainbow Lorikeets on their bodies, but that the event had not actually been observed.
WESTERN AUSTRALIA Information Sources
Dept of Conservation and Land Management, PERTH
David Lamont, Senior Conservation Officer, phone 00618-9334-0423, fax 00618-9334-0278
A copy of David Lamont’s article in Eclectus 3, October 1997 entitled "An Avian Weed in the West" is enclosed. I called him to clear up a number of questions raised in this report.
David Lamont said in a phone conversation on March 3, 1999:
His estimate of the current RBL population is 4000 and that the range has expanded. The
RBLs have remained in the mature suburbs of the city, due to the large variety of suitable
food trees, without supplemental feeding. The RBLs have not expanded into the new suburbs
of Perth or the WA bush due to the lack of suitable food resource. There has been a
decrease in the honeyeater population of Kings Park in the centre of Perth. That while he
would love to say they had, the RBLs had not expanded into the fruit growing area they
were close to as mentioned in his ‘97 report. That RBLs preferred roosting in Norfolk
pines and close to water. That he had seen the flocks of RBLs roosting in downtown Cairns,
and had suggested to the locals they should get rid of them, but they didn’t seem
very impressed with the idea. That RBLs had been observed fighting over nest hollows with
Australian Ringnecks, but the victor was not always predictable. That evicted bats had
been found under a tree on a golf course with beak marks possibly made by RBLs on their
bodies, but no the event had not actually been observed. That the Purple Crowned Lorikeet
was not a worry now, since it tended to remain in the WA Bush, whereas the RBLs remained
in the suburbs.
This information was the subject of an email (enclosed) to him for confirmation on 4 March 1999. In a telephone call on 19 March 1999, he said he had not received the email, so I faxed it to him that day with some further questions (enclosed).
A reply was received on 4 May (enclosed). Using David Lamont’s figures provided at
that time, I calculated the increases in population to the geometric mean (1414) of his
Feb 1996 estimate (1000-2000) as:
-from 6 in 1960 to 1414 at end 1995 (Feb 1996): an exponential increase of 16.8% per year
-from 1414 at end 1995 to 4000 in Dec 1998: an exponential increase of 44% per year over 3
breeding years. (This figure would range from 59% if the 1000 low estimate is used to 26%
for the 2000 high estimate)
On 4 May I called David Lamont to confirm the start date and population, to check the
reason for the anomalous figures in population increase before and after 1996, and to
question the correctness of the end population of 4000 based on previous rates. David
said:
That the start population was not the 6 birds from Rottnest Island, which according to
information from a Peter Coyle was believed to have reached the mainland coast 100 Km
south of Perth, and had died out. That according to John Long the author of Introduced
Birds of the World, the Perth population came from a release made by Stan the Gardener as
he was known as, a gardener with the University of Western Australia, who had released 11
birds in 1966, and that this was the start figure and date he had used in his life table. That the end figures according to the life table he had calculated should be 2734 in
1998, not 4000 as he had previously said. That Marion Massam of CALM had estimated a total
population of about 1000 in 1994. That he had knowledge of trees where 100 and 200 RBLs
roosted at night. That in his opinion Rainbow Lorikeets were a weed with wings and he did
not mind if I quoted him.
I requested a copy of his life table which he sent (enclosed). Using his new start figure of 11 in 1966, and his revised 1998 end population figure of 2734 instead of 4000, the exponential increase re-calculates at about 18-19% both before and after 1996. Marion Massam’s estimate of 1000 in 1994 quoted by David Lamont calculates as a 17.5% increase from 11 in 1966.
Agricultural Dept, Protection Services, PERTH
Marion Massam, Vertebrate Pests Officer, phone 00618-9366-2301, fax 00618-9366-2342
I sent a faxed request on 8 March 1999 to Marion Massam. Not having heard from her a
few weeks later I called her. Marion Massam said in the phone conversation:
That RBLs are not listed as a pest in Western Australia. Major fruit crops grown in the
Perth area are stone fruit, table grapes and wine grapes. That no complaints have been
received by her office about RBLs on any crops. That Silvereyes are a major pest, and
various species of native parrot are a problem to fruit crops. Valuable crops such as
table grapes are netted against birds. That Blackbirds, Starlings and Sparrows are not
present in Perth nor wanted, and a lot of work is done at the border with South Australia
to ensure these pests did not enter Western Australia.
Curtin University, PERTH
Professor Brian Collins, Dean of Science
phone 00618-9266-2838, fax 00618-9266-3747, email: b.collins@info.curtin.edu.au
On hearing David Lamont’s opinion that the Honeyeater population of Kings Park was
decreasing I looked for independent confirmation. Learning from the Research List
(enclosed) published by Birds Australia of Brian Collins’ work with Honeyeaters in
Western Australia, I sent him a email dated 24 March 1999 (enclosed) asking him for data
on RBL effects in Kings Park and the Perth Suburbs.
He replied by email (enclosed) on May 24 1999.
Edith Cowan University, PERTH
Professor Harry Recher, Foundation Professor, Environmental Management
phone 00618-9400-5758, fax 00618-9400-5717, email: h.recher@cowan.edu.au
For further confirmation about David Lamont’s opinion that the Honeyeater
population of Kings Park was decreasing I followed up his suggestion that I contact Prof
Harry Recher who was carrying out research into this. I sent an email dated 28 May 1999
(enclosed) asking him for data on RBL effects in the park and the Perth suburbs.
He replied by email (enclosed) on May 31 1999, and later sent a number of papers relating
to bird populations in Kings Park, Perth, and other areas of Australia. A population
census from Kings Park, Perth from 1927 to 1995 is enclosed.
SUPPORTING DOCUMENTS
Email to D
Lamont, 4 March 1999
Fax to D
Lamont, 19 March 1999
Email from D Lamont, 3 May 1999
Life table (liftab.doc) from D Lamont, 3 May 1999
Email
attachment from D Lamont, 30 Aparil 1999
Fax to M Massam, 8 March 1999
Email to B Collins, 24 March 1999
Email from B Collins, 24 March 1999
Email to H Recher, 28 May 1999
Email from H Recher, 28 May 1999
Extract census list from Recher, H.F, Impact of Wildfire
on the Avifauna of Kings Park, Wildlife Research CSIRO 1997
OTHER REFERENCES
Forshaw, J.M, Australian Parrots, Lansdowne Press 1981
Long, J. L, Introduced Birds of the World, Reed, 1981
Pizzey, G, A Field Guide to the Birds of Australia, Collins 1982
HANZAB, Handbook of Australian, NZ, and Antarctic Birds Vol 4, Oxford 1999
Lamont, D, Rainbow Lorikeets: An Avian Weed in the West, Eclectus Oct 1997
Recher, H.F, Long Term Changes in the Relative Abundance of Birds in Kings Park
Perth WA, Conservation Biology, 1991
Recher, H.F, Impact of Wildfire on the Avifauna of Kings Park, Wildlife Research
CSIRO 1997