Size matters: predation risk and juvenile growth in North Island brown kiwi (Apteryx mantelli)
This study investigated how predation risk in North Island brown kiwi changes as the birds grow and develop. Over a 10-year period, 53 adult and 126 young kiwi were radio-tagged at Lake Waikaremoana and studied to determine survival rates, causes of death, and rates of growth. Predation loss amongst adults was low (2.49% year-1) and caused mainly by ferrets. Young kiwi suffered intense predation from stoats during their first four months of life, but thereafter became too large (> 800 g) for stoats to kill.