Under what conditions is Monkey King visible when on a tree?

While perched on a tree, Monkey King is hidden from sight. He can only be seen with flying vision.

Flying vision gives unrestricted vision in an area, so it is not blocked by trees or obstacles and can see all elevations.

Sources of Flying Vision

• Towers do not have flying vision and the ranged creep has flying vision so be careful when you are perched on a tree near a lane.
• Monkey King can also be seen when standing 2 levels of ground higher than the tree he sits on, allowing wards to spot him when the ward is on an elevated ward spot.
• However, he cannot be seen when getting hurled in the air by spells (e.g. Toss). Only standing on high ground may grant vision over him.

Another important thing to note is that although Monkey King is shown to be at an elevation he is still considered to be on the ground. The height is part of the animations. Hence spells like Mirana's arrow and Io's spirits affect Monkey King.

• Monkey King is not invisible when on a tree so true sight is not required.
• He is visible while jumping between trees even to grounded units.
• During the leap and while on a tree, Monkey King gains flying vision, but has his vision reduced to 800. (Moonshard affects his vision but Nightstalker's Darkness does not)

If Monkey King is not moving, consider Monkey King to be 1 2 levels higher. If you (or a ward) are two steps higher than the tree he is standing on, then you can see him.

If he is moving, then he is on the same level as you, but vision can still be blocked by trees.

Flying vision always works, as well as other sources of vision.

And of course, the best solution is to pick Timbersaw and stun him :)