Valmiki Ramayana Yuddha Kanda Sarga 103 Shloka 27

रामस्य Rama's, कामरूपिणः which change form as per their will, सुपर्णरूपाः form of eagles, ते they, विशिखाः shafts, महाजवान् great speed, सर्परूपान् snake forms, सर्वान् all, तान् of them, शरान् shafts, जघ्नुः flew

Those shafts of Rama in the form of eagles which could change their form at will, destroyed the serpent forms and they flew at great speed.