Written by Juzah Zammit-Ross
The Antipodes Island Mouse Eradication operation will take place in the winter months of 2016 with the application of cereal bait Pestoff®20R by helicopter. The status of the outer islands will play an important role in the security of vulnerable terrestrial bird, invertebrate and plant species. Bollons Island is the only outer island that we have managed to visit so far as the rest are surrounded in steep cliffs. Recently we have declared confidence that there are no mice on Bollons Island and so it acts as an important sanctuary and reference for the biodiversity of the island group. Monitoring the other outer islands will determine whether mice are present or not, and this information will influence the extent of the treatment area for the baiting operation during 2016. Monitoring for the presence of mice on the outer islands of the Antipodes group is likely to occur in autumn 2015. If more of the outer islands are found to be mouse free they may also be home to some species no longer found on the main Antipodes due to predation and competition for resources by mice.
Leeward Island – Area 12.5 hectare, located approximately 45m east of the main Antipodes Island. This island is to be monitored for the presence of mice in 2015.
East Windward Island – Area 8.5 hectares, located 540m north west of the main Antipodes Island. This island will be monitored for the presence of mice in 2015.
West Windward plus islet- Area 7 hectares, located approximately 1100m west of the main Antipodes Island. This island will be monitored for the presence of mice in 2015.
Orde Lees Islet –Area 1.8 hectares, located approximately 50m north west of the main Antipodes Island. This island will be included in the baiting operation in 2016 because of its close proximity to the main Antipodes Island. It is within the swimming range of mice.
Archway Island- Area 6.3 hectares, located approximately 1500m north east of the main Antipodes Islands. This island will be monitored for the presence of mice in 2015 to confirm the assumption that it is mouse free because of its distance from the main island and proximity to mouse free Bollons Island.
Bollons Island- Area 52 hectares, located 1500m north east of the main Antipodes Island. We are confident that this island is mouse free so it is an important refuge for terrestrial bird, invertebrate and plant species because of the lack of direct predation and competition for food resources. See the recent Blog on Bollons Island for more details.
Rock stacks – There are also 21 rock stacks within 600m from the main Antipodes Island and they make up an area of approximately 3.3 hectares in total. These rock stacks will be included in the treatment area for baiting due to their close proximity to the main Antipodes Island.
Monitoring tools used to assess whether mice are present or not on these outer islands will include tracking tunnels, traps and possibly the use of a rodent detector dog. Access in most of these cases is limited to helicopters.