A pair of robins use a maple tree as a platform on which to build their nest.
A hawk eats a white-footed mouse during the day and as a result that mouse is not available to an owl the following night.
A gypsy moth eats leaves of an oak tree.
A pack of hyenas chase a lone lion away from a dead zebra so they can feed on it instead.
An ant colony protects an acacia tree from plant-eating insects and receives a place to live and food in return.