1. Hooting: Owls use their hoots to communicate with each other, and the pitch of the hoot can indicate the owl's size, strength, and aggression. Deeper hoots are typically associated with larger, more dominant owls.

2. Wing-flapping: Male owls will also flap their wings to display their strength and size. This can be done in a variety of ways, including clapping the wings together, beating the wings against the ground, or flying in a zigzag pattern.

3. Chasing: Male owls will sometimes chase each other in order to establish dominance. This can be a dangerous activity, as owls can inflict serious injuries on each other with their sharp talons.

4. Fighting: In some cases, male owls will actually fight each other to determine who is the dominant male. These fights can be very intense, and can sometimes result in serious injury or even death.

The outcome of these contests is important for male owls, as it can determine their access to mates and territory. Dominant males are typically more successful in attracting mates and defending their territory from other males.