The masting cycle of the southern beeches, Nothofagaceae, is synchronised by climate cues. Mass seedfalls provide resource pulses at 3–5-year intervals which drive cascading shifts in distribution, abundance and population dynamics of the whole beech forest community, from native invertebrates and seed-eating birds to introduced predators. Forest rodents (wild house mice (Mus musculus) and ship rats (Rattus rattus)), continue breeding over the winter after a heavy seedfall, reaching high abundances by late spring and early summer followed by a sudden crash in autumn and winter. Juvenile mortality in stoats (Mustela erminea) is much lower than usual, leading to a large cohort of newly independent first year stoats searching for prey just as the rodents are declining. Predation on forest birds is most intense during the post-seedfall summer, slackening as young stoats starve. These predictable events enable conservation managers to organise expensive and timely stoat and rat control programmes, with good effects for populations of native birds in the managed areas. An independent research programme used the same cues to catch, mark and release 134 stoats during the seedfall year of 1979–80. Fourteen of them were retrieved to confirm that baculum weight and cementum annuli are reliably linked with known age.