In the same week Prime Minister John Key was setting out his plan for making rats, stoats and possums extinct in New Zealand, Labour was starting to grapple with a pest problem of its own: the male List MP.
Key's goal was to make New Zealand pest-free by 2050. The conservationists cheered aloud.
But renowned ecologist Richard Prosser, who is also a NZ First MP, smelled a rat. It seems he had heard of something like this before. He knew of a woman who'd swallowed a fly. She had then swallowed a spider to catch the fly, swallowed a bird to catch the spider, swallowed a cat to catch the bird and so on. Nobody knew why she'd swallowed the fly, but it didn't end well.
The moral was that you don't mess with the circle of life. He predicted the same fate for Key's project. He set out why. Stoats eat rats and cats eat rats and both would only eat more birds if there were no rats. He then said there would always be rats: "No human society in history has succeeded in exterminating the rat."
The truth of that observation will also soon be causing headaches for Labour.
Labour's problem is that its males, like Prosser's rats, have proved remarkably resilient to efforts to drive them out.
Damien O'Connor, Stuart Nash and Kelvin Davis are all prime examples of Labour men who have evolved to survive the greatest threat to their existence: Labour's push for more women MPs.
At some point, all three former list MPs were given list rankings that would have sent them to Siberia. All three managed to defy the odds and win electorates back off their rivals to get back into Parliament.
Trevor Mallard has taken a more unusual evolutionary pathway. Rather than relying on his electorate for safety, Mallard this week announced he was giving it away in 2017 and instead throwing himself on the mercy of the list. He may regret it. For 2017 is also the year Labour has set itself a target of getting at least 50 per cent women in the caucus.
For his pest programme, Key at least had the sense to set a deadline well beyond his political lifespan. Labour was not so clever. Depending who you talk to, its goal is now described variously as a quota, a constitutional requirement, an aspirational target, a printing error or a complete mistake. That is because achieving it will require drastic action that goes against the less official rule of Labour's list ranking process: to protect sitting MPs.
Labour was supposed to reach 45 per cent in 2014 but fell short, partly because the success of those pesky males in their electorates deprived women on the list of a place in Parliament.
Labour has 27 electorates - 10 held by women and 17 by men. That is unlikely to change much in 2017.
To achieve the goal in 2017, at least the first eight names on the effective list (those who will not win electorates) must be women, after leader Andrew Little.
That puts people like David Parker and Trevor Mallard on precarious ground, let alone any newcomers.
The list ranking process will test just how serious Labour is about the quota. Labour in 2013 was so serious it even put it in its constitution. Its ruling council can hardly just pay lip service now.
Wary of an exodus of males from the list, Labour has now made it harder for candidates to refuse to go on the list. That will now require approval from the party president, leader Andrew Little and the Maori vice-president, currently Nanaia Mahuta.
That is for purely cosmetic reasons. The party has copped flak for obsessing over identity politics in the past, not least its swiftly abandoned "man ban" proposal to allow woman-only electorate selections. It is in the process of trying to ensure only women get in without looking like only women will have a chance.
If Prosser really wants to study the life-cycle of an endangered species, he need only ask Labour's male list candidates.