Hummingbirds fly by day when nectar sources such as flowers are more abundant. Flying low allows the birds to see, and stop at, food supplies along the way. They are also experts at using tail winds to help reach their destination faster and by consuming less energy and body fat. https://www.birdzfly.com/7-types-of-birds-that-look-like-robins-but-arent/ Research indicates a humming... https://www.birdzfly.com/