It is said that during the Spring of Arda, when Yavanna planted her seeds, "beasts came forth and dwelt in the grassy plains, or in the rivers and the lakes, or walked in the shadows of the woods." However singing birds didn't appear yet "for these things waited still their time in the bosom of Yavanna; but wealth there was of her imagining."
However when the Two Lamps where destroyed and there was no light in the Outer Lands, the Valie put them to sleep and they stopped growing during the Sleep of Yavanna, until there would be light again. Only Melkor's beasts roamed the earth in the shadows, that were kept at bay by Oromë the hunter.
After the awakening of the Elves, some of the kelvar were said to have been inhabited by powerful spirits. Most famous among these were the great Eagles that overlooked events in Middle-earth from their mountainous eyries.
Kelvar is an Elvish word meaning "animals, living things that move", probably derived from the stem KEL-, meaning "go" or "run". It has been suggested that kelvar is a Quenya word, and that the (unattested) singular form would likely be kelva. The terms kelvar and olvar, then, refer respectively to animal and plant life, and are essentially equivalent in meaning to fauna and flora.
- J.R.R. Tolkien, Christopher Tolkien (ed.), The Silmarillion, "Quenta Silmarillion: Of Aulë and Yavanna"
- J.R.R. Tolkien, Christopher Tolkien (ed.), The Silmarillion, "Quenta Silmarillion: Of the Beginning of Days"
- J.R.R. Tolkien, Christopher Tolkien (ed.), The Silmarillion, "Index of Names"
- J.R.R. Tolkien, Christopher Tolkien (ed.), The Lost Road and Other Writings, Part Three: "The Etymologies", p. 363
- Helge Fauskanger, "Quenya Corpus Wordlist" (accessed 15 March 2011)
- J.R.R. Tolkien, Christopher Tolkien (ed.), The War of the Jewels, "Part Four. Quendi and Eldar: Author's Notes to Quendi and Eldar", p. 416 (note 33)
- J.R.R. Tolkien, "I-Lam na-Ngoldathon: The Grammar and Lexicon of the Gnomish Tongue", in Parma Eldalamberon XI (edited by Christopher Gilson, Arden R. Smith, and Patrick H. Wynne), pp. 27, 56