Bill Benfield writes in his book The Third Wave (pp 76-77), on the use of brodifacoum poison, an anti-coagulant used by the Department of Conservation in NZ to kill pests. It is seen under the trade names of Talon and Havoc. An animal may get a small sub-lethal dose of brodifacoum, and later more doses until a critical poison level is reached & the victim dies. A single sub lethal dose however can remain with an animal for its whole life. Brodifacoum has a half life of 157 days in the soil. Some insects can consume brodifacoum baits and have no ill effect but of course if they are part of a bird’s diet they can be catastrophic.
As DoC do not monitor insects before and after brodifacoum operations, the consequences of their activities on endangered species is unknown.
This is how it was that the Auckland Regional Council poisoned nearly 60% of the resident population of endangered North Island dotterel at Tawharanui Regional Park in 2004: through eating brodifacoum baits and poisoned sand-hoppers!
When I read of these incidents I’m always left pondering as to whether the NZ agencies that purport to be saving our native birds are actually being truthful?
Connect the dots here…
1) DoC doesn’t monitor insects before & after poisoning operations
2) Insects eat brodifacoum
3) Dotterel EAT insects
4) 60%, in this instance, of the already endangered dotteral population dies
Is this really rocket science people?
REFERENCES: All references to Bill Benfield’s information are listed in his book The Third Wave.