The ability of Spotted-tailed Quolls to locate and consume meat baits deployed during a simulated aerial baiting program

A report to the Australian Alps Liaison Committee
AJ Murray, CA Belcher, RN Poore and J Darrant, February 2000

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Introduction

Spotted-tailed Quolls (Dasyurus maculatus) are marsupial carnivores that are confined to forested habitats in southeastern Australia and Tasmania. They are the largest extant dasyurid species on mainland Australia, and the only surviving species of Dasyurus in southeastern Australia.

Nationally, the conservation status of the Spotted-tailed Quoll is listed as “vulnerable”. It is listed as “endangered” in Victoria, and “vulnerable and rare” in New South Wales. Threats to the species in the past have included widespread habitat removal (primarily for agriculture and pastoralism) and persecution by settlers (trapping, shooting and poisoning) due to the threat the species poses to poultry. An epidemic disease may have affected the species in the early part of the 20th century. Current threats to the species are thought to include habitat fragmentation and modification, and competition from introduced predators such as the Red Fox (Vulpes vulpes) and the Cat (Felis catus).

Poisoning programs to control Dingoes (Canis lupus dingo), feral dogs (Canis familiaris) (hereafter referred to inclusively as “wild dogs”) and foxes are believed to be a potential threat to populations of the Spotted-tailed Quoll (Mansergh and Belcher 1992). One method of poisoning that potentially poses a significant risk is aerial baiting to reduce wild dog numbers, which takes place in some forested habitats in New South Wales. This form of bait deployment uses uncooked (air-dried) 250g kangaroo meat baits injected with the toxin 1080. Helicopters are used to distribute the baits. Baiting programs carried out by Rural Lands Protection Boards (RLPB) in southeast New South Wales adopt a bait distribution frequency of approximately 40 baits per kilometre of flight transect, whereas the NSW National Parks & Wildlife Service drop baits at a frequency of 10 baits per kilometre.

A simulated aerial baiting program was carried out in Tallaganda State Forest (southeastern New South Wales) in order to determine what percentage of a population of Spotted-tailed Quolls were able to locate and consume aerially-deployed meat baits. The trial replicated a standard RLPB aerial baiting program except that the baits were injected with a non-toxic biomarker, a dye called Rhodamine B. rather than the toxin 1080.

Three weeks after bait distribution, a cage-trapping program targeting Spotted-tailed Quolls was undertaken in Tallaganda State Forest over a period of 12 days. Sixteen quolls were captured, sedated and had eight vibrissae (whiskers) removed for analysis. Rhodamine B is laid down in the follicles of hair, and is easiest seen and most consistently laid down in vibrissae. Under ultraviolet light the dye glows, therefore indicating that bait ingestion has taken place.

Analysis of the vibrissae indicated that 10 of the 16 quolls captured had consumed Rhodamine B-injected baits. Both male and female quolls had located and consumed baits, including three of the four females captured that had pouch young.

The result that over 60% of the sampled quoll population were able to locate and consume an aerially-deployed meat bait in a single baiting operation suggests that aerial baiting at the intensity used during this trial in forested habitats may pose a serious risk to populations of this species.

The results suggest that land management agencies that employ aerial baiting in areas inhabited by Spotted-tailed Quolls should review their use of the method, and consider the use of techniques which reduce the risk of quolls locating and consuming poison baits.