The fatal flaw in New Zealand birds’ nests

Department of Conservation —  27/11/2017

New Zealand’s birds aren’t known for being particularly savvy when it comes to defending themselves from introduced predators.

For a start, many of them can’t fly, a serious disadvantage when your enemies are land-based.

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New Zealand’s flighless takahē. Photo: jokertrekker

On top of that, instead of running away when they’re in danger, our birds have evolved to stay still and rely on camouflage to avoid being seen. This might have worked a few hundred years ago when their only predators were other keen-eyed birds, but now they have animals like stoats, possums and rats to worry about. These animals rely on their keen sense of smell to find prey, so freezing on the spot is the opposite of useful.

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Camouflaged kākāpō. Photo: Mike Bodie

The nests that New Zealand’s native birds have been successfully raising chicks in for millennia have suddenly become unsafe with the introduction of these new predators too. The problem with the homes of birds like kiwi, kea and kākā is that they’re missing an important feature – a back door.

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North Island brown kiwi burrow

A nice hollow log or a burrow in the ground might seem like a great place to lay your eggs. You would be sheltered from the elements and hidden from the view of hungry predators. The problem is, these new, introduced predators don’t hunt with their eyes, they hunt with their noses. This makes it much easier for them to find your cave-sanctuary, and when they do, you’ve got nowhere to go. There’s only one entrance and exit, so if they come in and block it, there’s no way you can escape.

 

It’s not that our birds are silly, they’re just unprepared. They spent thousands of years on an island without furry, toothed mammals to worry about. New Zealand’s predators were birds like the giant Haast’s eagle, so it made sense to stick close to the ground and raise your chicks in burrows. But when humans came we brought with us some very strange animals. Furry predators with sharp teeth and quick feet. Our birds just haven’t had time to adapt to this new threat yet.

But there is hope. We’ve committed to protecting our native animals with an ambitious goal to rid New Zealand of stoats, rats and possums by 2050. Find out how you can become part of the Predator Free 2050 movement on the DOC website.

2 responses to The fatal flaw in New Zealand birds’ nests

  1. 

    They were superbly adapted to the world they faced before man: why fly when you can hide in burrows. Why come out during the day, when your predators are most active. Kakapo and others weren’t prepared for boots, guns, night vision lenses and more, and how could we expect them to be. It’s our duty to protect them from our own damage.

  2. 

    I recently saw a stoat out in daytime, bounding down a path towards me whilst walking in Westland. They’re very cute which belies their deadly abilities.