From The Guardian

Ecologists say some bodies of water may already have passed the tipping points from which they may never recover

As David Klee nosed his boat out into the channels of Whangamarino, he saw the birds were dying. Hundreds were already dead, floating, the sheen of their feathers dulling in the scum near the banks of the river. Others, he could tell, would be dead soon: flocks that should have been sent flapping in alarm by the boat’s passage sat placid, unmoving in the water.

Often, the bird’s legs go first, says Klee, the local game bird manager for Fish & Game New Zealand. Instead of paddling, they start scooping their wings through the water to propel themselves forward, a grotesque butterfly stroke. The poison works on the extremities, attacking nerves that thread down the limbs and wingspan. Then, the muscles of the neck weaken and seize: unable to hold the weight of the head, they droop forward, slip underwater, and the birds drown.

“This wetland is slowly dying around us,” Klee says. “We’ve seen these massive shifts occurring.” As he stands in the thick grass of the river shoreline, the yellow-brown water runs slow and opaque. Downstream, a dead koi is floating, the sheen of orange and white scales starting to peel upward as it bloats.

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