Probably an animated children film from the 90's.
Small aliens invade earth and land in the forest and evntually defeated by the animals I think or maybe some small other creatures. (the humans never knew they were invaded lol)
I remember the first secne with the aliens, they were flying above a soccer staduim or watch the game on the screen in the space ship and they were wondering why all these people are chasing this ball.... they thought it was very valuable.
(maybe they kidnaped and impersonated one of the animals)