Fecundity, pouch young survivorship and breeding season of the northern bettong (Bettongia tropica) in the wild.

Abstract

Reproduction in a wild population of northern bettongs (Bettongia tropica) was studied at Davies Creek in northeastern Queensland between November 1994 and February 1997. Using mark-recapture, we recorded 88 individual pouch young (PY) during the study (34 male, 45 female, 9 unknown sex). Using captive-derived growth equations we estimated that 90 % of PY survived to permanent emergence from the pouch (PEP). Birth of a new PY coincided with PEP of the previous young 78 % of the time; 12 % of births occurred within 2 - 8 weeks of PEP while the remaining 10 % probably died before PEP. 96 % of adult females carried PY at the time of capture. B. tropica bred continuously, with no significant differences in numbers of births recorded in different months. Few young that were marked in the pouch were captured as sub-adults, and none were captured as adults. Limited data on longevity indicated that B. tropica can live to at least 5 years. Our data suggest that B. tropica has a high reproductive potential; however, the fate of PY after PEP remains poorly known; and this may represent the period of greatest bettong mortality.