Wildlife ranger Ally Macaskill and Max who wears the GPS locator
Dogs wearing global positioning systems (GPS) are being used to help monitor one of Scotland's rarest birds.
Wildlife Ranger Ally Macaskill is using two German shorthaired pointers to help him track birds such as black grouse at Perthshire's Schiehallion estate.
The dogs wear GPS collars as they track the birds. Their precise location is then relayed to a handset carried by Mr Macaskill on the estate.
It is also being used to track species such as hen harriers and ptarmigan.
The John Muir Trust, who overseas the estate, has employed two dogs, Max and Gus, to monitor bird breeds in the area.
Mr Macaskill estimates there are about 25 male grouse on the periphery of the trust's property.
The birds are among the most rapidly declining breeds in the UK, with numbers in Scotland falling sharply in the past two decades
Max and Gus monitor the grouse by sniffing them out and standing still (on point) for long enough for the ranger to get up next to them.
Man and dog then gradually work alongside each other until the bird is flushed out of the heather, allowing Mr Macaskill to identify the species.
He said: "I've been very impressed with these GPS collars, which I saw used during trips to Scandinavia.
"They indicate whether the dogs are on the move or on point. When they get on point the collars mean I can get there quickly, with more chance of seeing what the dogs have found."
As well as the mapping function on the GPS collars, the ranger can also download their movements later on to a computer to work out what pockets of ground have been covered.