A love sick capercaillie who is becoming increasingly aggressive on his hunt for a mate has killed his love rival in a fight, it's been revealed.

Walking trails on the Glen Tanar Estate in Aberdeenshire were closed last week after the male bird started "displaying" and "holding it's ground".

The activity, known as "lekking", is designed to entice visiting females.

However, female capercaillie won't be interested in mating until April and rangers fear that the aggressive cock could mistake a walker for a potential mate or a rival for its territory.

Last year, one path on the estate was temporarily closed to visitors after another male seeking a mate pounced on a cyclist with its scissor-like beak.

Colin McClean, the estate's wildlife manager, said last year's aggressive capercaillie was no longer a threat, however, as it was killed by this year's bird.

He said: "It's very likely that he killed another male capercaillie in a fight last March.

"That bird had previously been aggressive to people and when he met his demise everything went quiet for a while.

"Now the victorious caper seems to have developed aggression to people.

"It's a bit of a pest but there we go."

Within the UK, capercaillie occur only within Scotland and 80% of them live in the Cairngorm National Park.

In the 1970s there was thought to have been around 20,000 of the bird in Scotland, but in 2014 that number had dropped to just 1000.