243 - Kiwi research

The main predators of juveniles are stoats and cats. A relative of weasels and also known as ermines, stoats were introduced to New Zealand in the late 19th century to control the rabbit population. Today, they kill about 60 percent of all North Island brown kiwi chicks. Kiwis also suffer from habitat loss, but the primary threats are animals introduced to New Zealand.

About 50% of all kiwi eggs fail to even hatch – sometimes because of natural bacteria, sometimes because the adult bird is disturbed by predators. 
Of eggs that do hatch, about 90% of chicks are dead within 6 months. 
70% of these are killed by stoats or cats, and about 20% die of natural causes or at the jaws and claws of other predators. 
Only 10% of kiwi chicks make it to six months.
Fewer than 5% reach adulthood.

http://www.willowbank.co.nz/kiwis-at-willowbank
http://www.whakatanekiwi.org.nz/resources/did-you-know.asp