Fauna in Grow: Song of the Evertree encompasses any of the animal life found in Alaria or on Worlds crafted by the Apprentice. Fauna can take many different appearances, especially in different Biomes, but not all Fauna in the game is interactive.
Birds
Birds appear in the sky over Alaria, the Where-Ever, and the various Worlds created by the Apprentice. At times they are barely visible as distant specks, while more often their shapes and sometimes even their colours can be discerned. Birds will not ever seem to either fly close enough that the Apprentice can get a good look, however (but a clever Apprentice can still get a better look using Photo Mode). Birds are never found on the ground.
Critters
Critters are any of the large or small four-legged creatures found in Where-Ever and on the Worlds crafted by the Apprentice. They can be tamed over time and even adopted and placed into various facilities around Alaria for later admiration and cuddles. For more detailed information, see Critters.
Fish
Fish can be found in just about any body of water in Alaria, Where-Ever or on Worlds crafted by the Apprentice. They can be caught using a Fishing Rod, and then sold or placed into any Nature Reserve in Alaria. (Do not place Fish into Coppertop, he's not an aquarium!) For more detailed information, see Fish.
Insects
Insects are the multi-legged (and sometimes winged) creatures crawling and flying around Alaria, Where-Ever or on Worlds crafted by the Apprentice. Although very skittish, they can be caught by sneaking up on them with a Bug Net, and then sold or placed into any Nature Reserve in Alaria. For more detailed information, see Insects.
Lykora
The Lykora is an enormous whale-like creature that flies around Alaria, singing a plaintive wordless song. Never landing, always flying, the Sky-Maiden, as she's also called, has long been thought of as Alaria's protector, and she certainly keeps the peace in the skies about the world of the Evertree. For more detailed information, see Lykora.
Mount
The Apprentice's flying mount is a four-legged, four-winged, fuzzy creature with horns and a long tail whose default name is Kazumi. The Mount has a special bond with the Apprentice allowing it to be called with a whistle whenever the Apprentice needs a ride into the boughs of the Evertree or elsewhere in Alaria. It is possible to rename the mount when the Apprentice and the mount first encounter one another, but it cannot be changed after that point. For more information about the mount, see Kazumi.
Younglings
Younglings refers to any of the sentient creatures found within the game. Many of them will interact with the Apprentice, and some are critical to assisting the Apprentice save the Evertree. For more information on the various races of beings who populate Alaria, see Younglings.