July - August 2004

Swallows are a sure sign that the quality of the water in the Rosedale Wastewater Treatment Plant ponds is improving.

The birds feed on midges that now breed in the water, and also act as a natural pest control. The reason for the clarity is that most of the processing is now done in tanks. Increasing oxygen levels also mean there is more food for other birds flocking to the ponds.

A recent survey by Bioresearches found that there are now 27 different bird species there, including three not seen before. They are the endangered brown teal, the New Zealand scaup, which is uncommon in the Auckland region, and the misnamed common sandpiper, a rare arctic migrant.