Currently (as of R23 in October 2015) Autumn Leafies seem to only spawn on Fallen Leaves, not directly on Autumnwood leaves, that's why they can nearly never be spotted sitting on top of Autumnwood trees. A neutral creature, the Autumn Leafi will fight back when the player attacks it, but will not attack first; different to his relative, the ordinary green Leafi, which will even only run away when being attacked. As Pets they might prefer to eat Horned Melons, Bread or Sandwiches - there is no diference in the pet-harvest of more or less modest Autumn Leafies.