fluttering
adjective
[ ˈflʌtərɪŋ ]
• (of a bird or other winged creature) flying unsteadily or hovering by flapping the wings quickly and lightly.
• "fluttering butterflies"
flutter
verb
• (of a bird or other winged creature) fly unsteadily or hover by flapping the wings quickly and lightly.
• "a couple of butterflies fluttered around the garden"
Origin:
Old English floterian, flotorian, a frequentative form related to fleet4.