Proceedings of the First Symposium on Marsupials in New Zealand

Field Methods

Field Methods

Trapping

Possums were caught at night in baited cage traps spaced at regular intervals through the forest. In area A the population was monitored continuously over 1966-75; traps were usually set at least one night per month, with two periods of more intensive study: (i) 1966 to 1968 described by Crawley (1973); (ii) May 1970 to December 1973 when 64 traps were set at 30 m intervals on a 210 × 210 m grid (4.4 ha) for four successive nights each month, with supplementary trapping in adjacent forest for 2–4 nights every 3–4 months. In area B a parallel trapping regime to that used in area A was adopted, 64 traps being set on the ground on a 210 × 210 m grid during the same nights each month from June 1971 to December 1973, (then less intensively until September 1974).