Where is scanning often recommended as being more effective for spotting a Kingfisher than watching the water surface itself?

Answer

From conspicuous perches overlooking clear water

Because the birds spend significant time surveying the water from above before plunging, viewing from a stationary, elevated perch is often the most successful method.

Where is scanning often recommended as being more effective for spotting a Kingfisher than watching the water surface itself?
Geographyhabitatbirdwildlifekingfisher