Stoats

• Stoats alone are responsible for up to 60% of kiwi chick deaths .
• Just to survive, a stoat needs to eat the equivalent of 12.5 fantail chicks every day.

Possums

• There are an estimated ( pg.15 ) 30 million possums in New Zealand, and up to 25 per hectare (10 per acre) in preferred habitats.
• Possums kill birds and chicks and raid nests for eggs, as well as stripping the forest canopy.
• Possums are also the host and carrier of the lethal disease, bovine tuberculosis, and, along with ferrets, are responsible for 70% of new infection in cattle and deer herds.
• TB infected possums live in about 40% of New Zealand .
• Sick and dying TB-infected possums come out onto farmland, where cattle and deer lick their carcasses .
• All cattle and farmed deer must be registered with TBfree NZ and regularly tested. Any animal found to be infected is slaughtered immediately and herd movement is stopped. Dairy and meat exports are worth more than $14 billion annually to New Zealand.

Rats

• Rats prey on small birds, chicks, eggs and insects in the forest.
• In ideal conditions a rat can produce 10 offspring every 8 weeks.
• Prolific seeding (’mast') years in South Island beech forests cause an explosion of rat and stoat populations. This year's mast (in areas being targeted with 1080) is estimated to generate four million rats .

Impacts of introduced mammalian predators on indigenous birds of freshwater wetlands in New Zealand.
New Zealand Journal of Ecology (2015) 39 (1): 19-33

Efficacy of chew-track-card indicies of rat and possum abundance across widely varying pest densities.
New Zealand Journal of Ecology (2015) 39( 1): 87-92