Efficacy of Feratox® cyanide pellets to control introduced brushtail possums on Middle Island
RESEARCH TRIAL PROTOCOL
Animal Control Technologies
in conjunction with
Connovation (NZ) and the
Queensland Parks and Wildlife Service (QPWS)
COMMERCIAL – IN – CONFIDENCE
Not to be published or reproduced without the consent of the authors
Table of Contents:
1. Executive Overview 3
1.1 Toxin welfare screening for possums: 4
1.2 Feratox® cyanide pellet possum bait: 5
1.3 Non target impacts: 6
2. Methods: 7
2.1 Site Selection: 7
2.2 Bait station use: 7
2.3 Free-feeding: 8
2.4 Bait application: Feratox® cyanide pellets: 8
2.5 Possum population monitoring: 8
2.5.1 Spotlight counts: 9
2.5.2 Possum track activity: 10
2.5.3 Carcass searches: 11
2.5.4 Camera monitoring: 11
2.5.5 Pre-feed bait uptake: 11
2.6 Non-target population monitoring: 12
3. References: 12
1. Executive Overview
The Keppel Islands, which are located within Keppel Bay (adjacent to the Capricorn Coast in Central Queensland) were cut off from the mainland approximately 6 000 years ago. Brushtail possums (Trichosurus vulpecula) are native to the adjacent mainland area and have been introduced to four islands in the bay, one of which (Middle Island) is the proposed site for this possum eradication trial.
In 2002 population estimates ranged from 4 - 11 animals per hectare (habitat dependant) on one of the islands (627ha North Keppel Island), compared to an average density on the adjacent mainland of 0.2 – 0.4 individuals per hectare (Strahan, 1995). Possums were most likely introduced to islands in Keppel Bay after European settlement as a harvesting source for pelts. Genetic analysis has not identified the possums on these islands as a unique sub-species. The abnormally high population densities support the theory that the possums were introduced into an environment with little or no natural predators, diseases or competition.
The impact of possums on the biodiversity of the islands has been extreme. Complete defoliation of localised stands of drought-stressed Poplar Gums (Eucalyptus alba) has occurred, and other negative impacts on the islands include the destruction of plant regeneration and tree plantings, destruction of bird nests, consumption of eggs, littoral / intertidal damage to native species, contamination of rainwater for human consumption in camping areas, and potential erosion problems associated with vegetation destruction. The possums cause conflict with campers with destruction of tents, equipment, and food, and their aggressive nature results in bites to campers and students (an average of one bite every two weeks in 2001).
Due to these concerns, QPWS (managers of the Keppel islands) have periodically controlled the possums on the islands with techniques including trapping and gassing, however the programs are labour intensive and only slowly reduce the population.
The emphasis of any...