My Account
Island weka threat
In the article headed, Strong feelings voiced on both sides of Kawau pest plan (MM Sept 25), it recorded that, ‘The fact that a certain proportion of the island’s weka and pateke would die due to secondary poisoning’.
The implication taken from the article is that the North Island weka would not die from eating the Brodifacoum poison, but rather from eating/scavenging on the rat carcasses or other carcasses poisoned by Brodifacoum.
The article then went on to say that taking some into captivity during the operation would ensure their populations were not jeopardised.
Your article is non-specific. It refers only to taking “some” into captivity to ensure the population was not jeopardised and that “a certain proportion” is going to die.
The Feasibility Assessment, on which the statement will have been based, states that the individual rates of mortality for North Island weka on Kawau are likely to be high (referenced on p.40). The Feasibility Assessment goes on to say:
“Kawau supports the largest island population of North Island weka and is considered a stronghold for the species whose population fluctuates widely on the mainland.”
To anyone who has observed the feeding habits of the North Island weka, it is hard to imagine that they would leave any cereal bait they came across untouched. That view appears to be supported by the Department of Conservation (DOC) science.
An article published by DOC on the Toxicity and Sub-Lethal Effects of Brodifacoum in Birds and Rats (A Literature Review as Science Conservation; CT Eason and EB Spurr) sets out a table of indigenous bird species, or sub species, who are at risk in areas where cereal bait of Brodifacoum could be used, as is planned here.
In that table, North Island weka are not only recorded under the column “probably would eat cereal based baits if encountered” but, in addition, the column records them as being known to have eaten cereal-based baits.
The extent of the bi-kill of North Island weka that will happen if this project proceeds will happen from both primary and secondary poisoning.
What is the “certain proportion” of the present weka population on Kawau that will be killed by the planned island-wide spread of Brodifacoum poison if this project proceeds?
It is my understanding that the entire western weka population of Tawhitinui Island was exterminated by a Brodifacoum poison drop in 1984.
Colin Bright, Hokimai Bay, Kawau Island
