The Ecology and Conservation Group
Elizabeth Hargraves

RESEARCH

Spatial and temporal analysis of little blue penguin foraging ecology

The little blue penguin (LBP), Eudyptula minor, is the world's smallest penguin; found along the southern coastline of Australia and around New Zealand. The North Island subspecies (E.m.iredale) breeds on shorelines extending down from the Northlands as far as the Waikato region in the west, and Gisborne to the east. This includes Little Barrier, Great Barrier, Mercury, and Tiritiri Matangi Islands.

Although listed as a species of 'Least Concern' by the IUCN Red List, LBP are in Gradual Decline in New Zealand. Throughout their range, periodic mass beach wrecks occur and post mortem studies have found poor body condition associated with starvation as the primary cause. At least one wreck event in Australia has been associated with large mortalities of pilchard (Sardinops sagax) and it is speculated that changes in the abundance or distribution of prey species may trigger mass penguin deaths.

Little blue penguin's major prey are small pelagic schooling fish, such as pilchard and anchovy (Engraulis australis), both of which are commercially fished in New Zealand. Little is known about the characteristics of the LBP's foraging range; spatially or temporally. The Department of Conservation is proposing to establish several marine reserves in the Hauraki Gulf, and baseline data is required to assess the success of these no-take reserves, in regards to this species. Recent developments in the miniaturisation and hydrodynamic design of satellite tracking instruments have made it possible to collect this data.

Satellite tracking and time-depth recorders will be placed on at least ten birds per study area and the data analysed in conjunction with estimations of prey abundance from bi-monthly mid-water samples. This study aims to elucidate how patterns of habitat use vary temporally and spatially, across life history stages, and relate these findings to penguin density and breeding success. It will be the first study to describe foraging range and dive profiles for the Northern subspecies of LBP.