As dawn breaks a distinctive bubbling sound carries through the air.

War cries of male black grouse.

They're here to compete for mating rights to the mottled-brown females.

On this battle ground, known as a lek, there's a distinct hierarchy ...and in the center of it all is the 'King'.

He's the champion fighter flaunting the biggest scarlet eye combs... and finest lyre tail feathers.

Popular with the hens, he wins the most mates, ...but every male wants his success.

Threats come from all sides.

Novice males, are just learning the ropes and are easily intimidated, ...but there'’’s one battle-scarred male who'’’s a serious challenger.

This Old Timer'’’ has sacrificed many of his fine feathers in combat and isn'’’t satisfied with a place on the edge of the action, watching the hens pass him by.

He challenges the King to a duel.

Both are heavy-weights at over four pounds... and closely matched.

The Old Timer rips out a clump of chest feathers.

The King retaliates The battle goes on for almost an hour.

Both sustain stabbing injuries to their chests.

until the King deals the final blow.