Quantifying seed dispersal by birds and possums in a lowland New Zealand forest

Declines in native birds in New Zealand have raised questions about whether seed dispersal limits plant regeneration and whether introduced mammals such as brushtail possums (Trichosurus vulpecula) can replace absent native birds. We determined the relative contribution to seed dispersal by birds and possums in native secondary forest at Kowhai Bush, Kaikoura. The number of seeds dispersed per hectare per day by each animal species was determined based on the number of seeds per faecal pellet, the number of faecal pellets per animal per day, and the density of animals per hectare.

Nest survival of birds in an urban environment in New Zealand

We compared nest survival of three urban bird species over two seasons in Dunedin City: silvereyes (Zosterops lateralis), a recent self-introduced native that is very abundant; blackbirds (Turdus merula), an abundant exotic species; and fantails (Rhipidura fuliginosa), a native species that occurs in relatively low numbers in some urban habitats. We also used artificial nests to compare nest predation rates between residential gardens and bush fragments isolated within a residential matrix.