wildlife management

In New Zealand, intensive, site-based conservation management of bird species is often focused on controlling threats from invasive species at a local scale. Such management may benefit species resident within the site but may be insufficient for mobile taxa whose movements extend beyond it through annual migrations, irregular nomadic movements, or exchanges of dispersing individuals in metapopulation networks.

Stoats are implicated in the severe decline of certain iconic endemic species in New Zealand. Stoats are notoriously difficult to control, as they are highly cryptic and often neophobic around control techniques such as traps and poison baits in tunnels. Stoats are often killed through secondary poisoning in both aerial and hand-lay operations targeting other mammalian pests. We prototype trialled a novel approach to poisoning of stoats: wild-caught ship rats that had consumed (and subsequently died from) a lethal dose of 1080 cereal baits in a captive facility.

As New Zealand attempts to become predator free by 2050, transitioning aerial 1080 (sodium fluoroacetate) operations from predator control to complete predator removal has become an important research objective. Aerial 1080 operations may not remove every last target animal, but they may be able to remove a very high proportion (> 0.99). We trialled a modified [dual] aerial 1080 operation for the removal of brushtail possums (Trichosurus vulpecula), ship rats (Rattus rattus), and stoats (Mustela erminea) at large spatial scale.

Lethal control of wildlife is commonly used by conservation practitioners for population control. In some areas of New Zealand, changes in land-use and management have led to large increases in pukeko (Porphyrio melanotus melanotus) range and numbers. This native rail is sometimes considered a pest species, as they are known to uproot vegetation including tree seedlings, grass and crops. Here, we provide the first data on mortality during a lethal control operation that aimed to reduce pukeko population size at Tawharanui Regional Park in the North Island of New Zealand.

In New Zealand we need to develop new control tools for the overabundant brushtail possum, which is an agricultural and environmental pest. In this study we evaluated the performance of a new microencapsulated zinc phosphide (MZP) paste (1.5% w/w nominal conc.) in a captive study and at six North Island field sites. In the captive study 14 out of 16 possums fed MZP paste bait died (87.5% kill ± 8.3% SE) with death occurring on average 165.4 minutes (± 5.5 SE) after first eating the bait.

The Australian brushtail possum Trichosurus vulpecula is a pervasive marsupial pest of New Zealand. Impacting on the native flora and fauna and the nation’s livestock industry as a vector of bovine tuberculosis, T. vulpecula is a priority for control and eventual eradication. Possum control at present relies on conventional trapping and poisoning methods. Efficient allocation of control depends on accurate quantification of abundance, which could be achieved with the implementation of non-invasive sampling schemes.

The horn length of male thar (Hemitragus jemlahicus) increased significantly with age, especially from birth to 5 years. Age, time of year, and body weight all influenced adult male horn length, but locality did not. Fewer than 1% of males produced horns of sufficient length to qualify as hunting trophies.

A significant recovery of food plants preferred by introduced deer (Cervus elaphus) occurred between 1969 and 1984 on 57 permanent plots in the alpine grasslands of northern Fiordland. During this period the deer population was reduced markedly by hunters operating from helicopters.