non-target mortality

Lesser short-tailed bats (Mystacina tuberculata) feed on arthropod taxa known to consume 1080 baits. Thus, they may be vulnerable to secondary poisoning after control operations for brushtail possum (Trichosurus vulpecula) using aerially broadcast 1080 baits. Short-tailed bat mortality was monitored during 11 days after 1080 baits were broadcast over their winter foraging area. Monitoring involved catching a sample of 269 bats as they arrived at a roost after foraging, then holding them in captivity for 48 hours.

Ongoing investigations into bird mortality caused by aerial 1080 poison operations to suppress pest populations will be required because the operational specifications continually change and improve. We summarise recent studies of bird deaths following 1080 operations and present six principles for use in prioritising future research into poison risk for bird populations. A decision tree (and supporting flow diagram) shows how the need for new surveys can be evaluated using these principles.

We collated 48 surveys of individually banded birds or birds fitted with radio transmitters that were checked before and after 1080 poison (sodium fluoroacetate) baits were aerially distributed to control brushtail possums (Trichosurus vulpecula) in New Zealand forests. The surveys were associated with 34 pest control operations from 1986 to 2009 and covered 13 native bird species, of which four were kiwi (Apteryx spp.). Sample sizes ranged from 1 to 46 birds (median 15). In 12 cases a sample of 1 to 42 birds (median 13) was surveyed in an untreated area at the same time.