OPINION: Apparently native robin populations lose their fear of rats after only one generation in a predator-free environment, imperilling their reintroduction from island sanctuaries to the mainland.
In the far-from-pest-free environment around the Beehive barely a week passes - let alone a generation - between incursions by one predator or another; be it the media, an opposition MP or a Cabinet minister on the prowl.
At the top of the food chain sits the prime minister, whose very whim represents the ultimate law of the jungle.
In such an environment, red in tooth and claw, it is no surprise that ACC chief executive Ralph Stewart, chairman John Judge and other members of the board, introduced from the private sector, have become road kill.
It took only an indication from Mr Key that there were questions to answer by Mr Judge and Mr Stewart to get the wrecking ball rolling; and there was no chance that ACC Minister Judith Collins would hold back.
This week's mayhem takes to five the number of careers that have been side-swiped by the ACC furore: Nick Smith, John Judge, Ralph Stewart, John McCliskie and Rob Campbell.
Coming hard on the heels of the class sizes debacle, it is the last thing the Government would have wanted as it tries to get back on an even keel, though a minister looking tough is never all bad.
On Monday ministers examined the entrails of the class sizes mess, and decided to share the blame around and move on.
But even for Mr Key, at the top of the food chain, the problems this week have still come thick and fast, and that is inexorably being reflected in the polls.
On Tuesday morning, during a "live chat" on the Stuff website, he admitted as much with characteristic self- deprecation.
Asked if he was surprised at Piri Weepu getting the nod as All Blacks halfback ahead of Andy Ellis, he said: "Yes, but I'm having a bad enough week without wading into the reasons on this."
By that afternoon, and into Wednesday, the flurry of bad news had become a storm with ACC at the centre.
But there was also the untimely news that the auditor-general would probe the convention centre deal, as well as the final acknowledgment that the Government would abandon its discriminatory treatment of families looking after adult disabled children, a backdown that could potentially cost hundreds of millions of dollars.
In harness with the U-turn over teachers, it will severely deplete both the Government's contingency fund and the provision for new spending in coming years, just three weeks out from an already tight Budget.
The Government's initial response was an abnormal blizzard of news, that on past experience the ninth floor of the Beehive will insist was planned weeks ago.
In short order, and in close formation with Mr Judge's resignation, came news about pepper spray in prisons and a loyal salvo of press releases from Leader of the House and Transport Minister Gerry Brownlee.
They included a rather superfluous reminder of some well-signalled "bad news": the re-release of the outcome of last year's decision to delay a rise in the petrol excise tax, confirmed as a 2c rise in the Budget, that will add about $30 a year to the average car's running costs.
Whether by accident or design, it looked for all the world like a case of "Never mind that, I have some less bad news".
The Government's woes have not been helped by Mr Key's increasing isolation on raising the superannuation age - even as he moves his position subtly towards . . . what? Possibly future talks about an increase in a way that will not breach his promise to hold the line or quit?
Nor did he help his side's case when he explained the backdown over class sizes as an example of the Government listening to voters, then changing its mind.
Talk about declaring open season on yourself and your programme.
At its peak on Wednesday the rising tide of controversy even crashed the online betting site iPredict as punters traded on the near-simultaneous resignation of Mr Stewart, the investigation into the proposed convention-centre-for-pokies deal and the spinoff for the future leadership of the National Party, in which Steven Joyce and Ms Collins are prominent.
Looking back on the last week and fortnight, the overall impression is of an accelerating sense of crisis, starting with the Budget.
Mr Key needs, urgently, to seize back the initiative.
He must find ways for his ministers to get back on the front foot before National's falling poll numbers become entrenched.
Next week's Cabinet meeting will not be a moment too soon.
And while he is at it, he might want to have a stern word with himself, too.
- © Fairfax NZ News