In which forest layer is the American Redstart most productively searched for, according to general guidelines?

Answer

Lower to middle strata (between 5 and 30 feet up)

Focusing attention on the lower and middle layers, specifically stated as being between 5 and 30 feet up, will be far more productive than looking at the very top of the tallest trees.

In which forest layer is the American Redstart most productively searched for, according to general guidelines?
naturebirdwildlifeidentificationwarbler