Valmiki Ramayana Yuddha Kanda Sarga 4 Shloka 89
Original Shlokaतस्य सानुषु कूजन्ति नानाद्विजगणास्तथा ।।6.4.88।। स्नात्वा पीत्वोदकान्यत्र जले क्रीडन्ति वानराः । अन्योन्यं प्लावयन्ति स्म शैलमारुह्य वानराः ।।6.4.89।।
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तथा that way, तस्य its, सानुषु in the mountain ranges, नानाद्विजगणाः different kinds of flocks of birds, कूजन्ति singing , वानराः vanaras, जले in water, स्नात्वा after taking a bath, उदकानि the water, पीत्वा drinking, क्रीडन्ति sporting, शैलम् mountain, अरुह्य climbing up, अन्योन्यम् one over the other, प्लावयन्ति स्म jumping
At that time different kinds of flocks of birds were singing in the mountain ranges. The vanaras after having taken their bath were drinking and sporting with water with each other (pouring water over another) climbing up the mountain.