Valmiki Ramayana Kishkindha Kanda Sarga 1 Shloka 20

पुष्पसञ्छन्नशिखराः treetops covered with flowers, मारुतोत्क्षेपचञ्चलाः shaken by the restless wind, मधुकरोत्तंसाः turbaned by black bees, अमी these, पादपाः trees, प्रगीताः singing, इव like

With the tops of trees covered with flowers, the black bees hovering (humming) over them, the trees, shaken by the restless wind look like singers. (The trees with the top decked with flowers, the bees like black hair on the head swaying in the wind look like dancing and singing)