Date: 30 September 2009
As part of research to discover exactly how penguins were exposed to brodifacoum, the Department of Conservation has commissioned further tests on penguin samples.
New results show low-level traces of brodifacoum in one of four penguins tested. The autopsy of this bird — carried out by the NZ Centre for Conservation Medicine (NZCCM) — showed none of the symptoms associated with brodifacoum poisoning. All four birds were very thin and had no body fat.
These results support earlier findings by NZCCM that starvation is the likely cause of death of penguins from the region.
DOC has now commissioned toxicology tests on nine penguins in total. Six had no traces of brodifacoum in their livers, and three had low-level traces ranging from 0.005 parts per million to 0.17 parts per million.
"From previous operations, we know that some species of birds do pick up brodifacoum baits, and we plan our operations to minimise risks — particularly to threatened species. Blue penguins are not a threatened species. They were not considered to be at risk from this operation, so we are trying to find out why three of nine blue penguins tested had minute traces of brodifacoum in their livers."
“We are constantly refining our pest-eradication operations, and as part of this process, we are seeking advice from a range of scientists on how we can identify the most likely pathway by which penguins were exposed to brodifacoum,” says acting Auckland Area Manager Phil Brown.
Tests on pilchards (taken from dead dolphins’ stomachs) have come back negative for brodifacoum. Further tests on pilchard samples are expected back next week.
Tests on dogs, dolphins, mussels and pipis have also come back negative for brodifacoum.