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Northern Territory |
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The Northern Territory covers an area of over 1,300,000 square kilometres (about six
times the area of New Zealand)
The Red Collared Lorikeet (Trichoglossus haemotodus rubritorquis) the western subspecies
of the Rainbow Lorikeet (Trichoglossus haemotodus moluccanus), differs mainly in
colouration from that species. It inhabits the northern quarter of the Northern Territory,
the Kimberly area in the north of West Australia, and the Gulf of Carpentaria coast in the
west of Queensland.
Tropical fruit losses in an average year approximate 2-3% for all flying pests, of which the greatest damage is caused by flying foxes, followed by parrots, then foliage and ground birds. The fruit crops grown in NT are mostly tropical and few are grown in NZ. Of those fruit crops common to both NT and NZ viz. Figs, Citrus, Nectarines, Peaches, Grapes and Passion Fruit, all had zero damage recorded from Red Collared Lorikeets in a 1992 survey commissioned after a year of very high damage from all flying pests. In addition in this year the following vegetable crops common to New Zealand all had zero damage recorded from Red Collared Lorikeets: Tomato, Zucchini, Cucumber, Egg Plant, Sweet Corn, and Maize.
Only one fruit crop common to NZ, the Guava, was reported as being damaged by Lorikeets, by 2 out of 128 grower responses according to the survey. The Guava is not a commercial crop in New Zealand. Additionally, one field crop Sorghum, was reported by 2 out of 128 grower responses in the survey, but according to another report the damage done by Red Collared Lorikeets to crops such as sorghum and other broad acre crops is totally insignificant.
The year 1992 in the Northern Territory was a year of unusual conditions, the long wet interfering with the normal flowering of the eucalypts. Birds and flying foxes appeared in large numbers in commercial crop growing areas due to a shortage of their normal food in the bush. Complaints from Rambutan and other growers were such that a special report was commissioned to determine the extent of the damage, and investigate methods of control.
The Rambutan (a fruit which has a very sweet pulp and which must be left on the tree to ripen fully) had been introduced about 20 years earlier, with plantations totalling 12-15,000 trees. During that time the fruit had not been recognised by birds or flying foxes as a suitable food, presumably because it is unlike any indigenous fruit, and is protected by long spikes and a moderately tough skin. The Rambutan was discovered in the harsh conditions of 1992 and growers who had not previously found the need to net their trees lost 90-100% of the crop to flying pests including Lorikeets (53%), Cockatoos and Corellas (18%), Flying Foxes (10%), Geese, Crows, and Honey-eaters. After this year most of the larger Rambutan growers netted their trees, achieving effectively zero losses from all flying pests.
Damage that same year to Mangoes was also high, damage being caused mostly by Flying Foxes (39%), then Lorikeets (17%), Sulphur-crested Cockatoos, Galahs, and Corellas (16%), Geese (9%), and Bower Birds (7%). In spite of the damage in that year, at the present moment no plantations of mangoes are netted, the losses from all flying pests being not considered a major threat to the industry.
Neither the Rambutan or the Mango are grown in New Zealand.
Since 1994, 2 permits to eradicate the Red Collared lorikeet have been issued by the Parks
and Wildlife Commission, in both cases to Rambutan growers. A total of 22 birds were shot
in 5 years state-wide as a result of these permits.
Competition with other Species
The range of the Red Collared Lorikeet in the Northern Territory is restricted to the northern quarter of the state. In this range the Red Collared Lorikeet co-exists in mutual competition with the following parrots and honeyeaters, all of which overlap in resource requirements either of food (mainly nectar or pollen) or nest sites (suitable nest holes) with it:
Parrots: Resource Overlap
1 Species Lorikeet nectar, pollen, nest sites
7 Species other Parrot nest sites
Honeyeaters:
Resource Overlap
3 Species Friar Bird
nectar
1 Species Miner Bird
nectar
15 Species Honeyeater nectar
No references could be found that interspecific competition between Rainbow Lorikeets and any other species for food or nest sites is anything other than normal.
Northern TERRITORY INFORMATION sources
Parks and Wildlife Commission
Dorothy Hunter, Permits and Licences, phone 00618-8999-4795, fax 00618-8999-4524
In response to an enquiry dated 1 March to Leone McDonald (enclosed), Dorothy Hunter sent a letter (enclosed) showing the number of permits issued over the last 5 years to eradicate the Red Collared lorikeet.
Parks and Wildlife Commission
Barry Scott, Senior Conservation Officer, phone 00618-8999-4758, fax 00618-8999-4793
On 8 March I phoned Barry Scott to enquire about losses caused by lorikeets in crops.
Barry Scot said in that telephone conversation:
That tropical fruit losses in an average year are about 2-3% for all flying pests
including the two species of flying fox.
I followed this with a fax request (enclosed) for further information on crop damage. Barry Scott suggested in a further phone call that I contact Primary Industries and Fisheries.
Dept of Primary Industries and Fisheries,
Tropical Horticultural Dept
Greg Owens, Technical Officer, phone 00618-8999-2292, fax 00618-8999-2049
Tom Price, Extension Officer, Field Crops, phone 00618-8999-2215, fax
00618-8999-2043
In response to an enquiry dated 4 March sent to Mike Poffley (enclosed) Greg Owens
replied with a report published in 1993 by the Primary Industry and Fisheries Dept of NT
entitled "Winged Vertebrate Pest Damage on Crops in the Northern Territory"
(extract enclosed).
In a telephone call to Greg Owens in March, I enquired the reasons for the high losses in
the Rambutan crop mentioned in that report.
Greg Owens said:
That the Rambutan had perhaps a 20 year growing history in NT, and there were now about
12,000 trees in the state. That up to 1992 very little trouble had been experienced by
Rambutan growers, but that 1992 had been the worst year in memory for bird damage and that
it was in this year that the Lorikeets discovered the Rambutan fruit. Growers had since
used netting to protect their fruit.
In response to a further enquiry dated 8 March (enclosed) to Greg Owens, Greg Owens sent a letter (enclosed) provided anecdotal data on various crops and flying pests.
Noting that HANZAB quoted sorghum as a crop predated by Rainbow Lorikeets, I sent a fax (enclosed) to Tom Price, the Field Crops extension officer, and followed it up the next day with a phone call:
Tom Price said:
That whether the Red Collared Lorikeet was a pest of field crops was not a very
difficult question to answer. That the damage done by Red Collared Lorikeets to crops such
as sorghum is absolutely minimal. That they would consider them in the Top End to be
totally insignificant in broad acre cropping. That they are in very small numbers on those
crops. That he had not ever actually seen a Red Collared Lorikeet eating maize.
SUPPORTING DOCUMENTS
Fax to Leone McDonald, 1 March 1999
Letter from Dorothy Hunter, 2 March 1999
Fax to Barry Scott, 8 March 1999
Fax to Mike Poffley, 4 March 1999
Extract (5 pages) from Lim, T.K etc, Winged
Vertebrate Pest Damage in the Northern Territory, Technical
Bulletin
No 209, Primary
Industries and Fisheries, NT
Fax to Greg Owens, 8 March 1999
Letter from Greg Owens, 17 March 1999 (2 pages)
Fax to Tom Price, 3 June 1999
OTHER REFERENCES
Forshaw, J.M.,
Australian Parrots, Lansdowne Press 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
Lim, T.K etc, Winged Vertebrate Pest Damage in the Northern Territory,
Technical Bulletin No 209, Primary Industries and Fisheries, NT