Turbulent winds present few problems for hovering birds -- their wings developed long ago to constantly adapt to sudden and strong gusts, hence the term "feathering" the wind. Developing blades with the same ability is the aim of Vestas, which has received DKK 15 million from the Danish National Advanced Technology Foundation to demonstrate that the concept works on blades for "very large" turbines. "We know it works in theory. That has been proved by experiments with small elements in a wind tunnel. We also know that it works in nature. The challenge is to construct adjustable flaps for turbine blades in order to reduce loads on blades and turbine structure and thus design much more cost effective turbines," says Carsten H Westergaard, manager of Vestas' office at the Danish national laboratory at Risø. The laboratory is also involved in the project along with the Technical University of Denmark.