IN THE COURSE OF A WORKING day, Derek Robertson could be rained on, bitten by midges, chased by a bull – and he wouldn't have it any other way.
Robertson is one of Scotland's leading wildlife artists, a profession requiring much patience and a high level of endurance of inclement weather, biting insects, and subjects that refuse to stay still. Robertson just shrugs.
"I almost think I've not had a good day if I haven't got nettle stings on my arms and a red face from sunburn," he says.
He answers the door of his Aberdeen home with a fine paintbrush in his hand. Although he does most of his sketching out of doors, the business of bringing a composition together happens here, in his front-room-turned-studio. Paintings and prints are hung or stacked: an evocative watercolour sketch of a cormorant and chicks; puffins on the Isle of May; three curlews against a lilac horizon.
Many of these works are on their way to Robertson's forthcoming retrospective at Waterston House, the new purpose-built HQ of the Scottish Ornithologists Club on the outskirts of Aberlady in East Lothian. In the attractive gallery space, long windows look out to Aberlady Bay Nature Reserve, where some of his subjects dwell.
"From as early as I can remember, I've always been fascinated by wildlife and nature, and also with painting and drawing. My mother still tells me about the time I ruined her new dining room wallpaper – I'd paint on anything I could get hold of! But the two things grew together. I can't remember a time I wasn't interested in both things."
Robertson, who grew up in Fife, studied at Duncan of Jordanstone School of Art in the late 1980s where he spent much of his time out of the studio sketching landscapes and wildlife. His work developed in two interwoven strands: one, painting delicate lifelike studies of birds and animals, the other making more abstract installations and assemblages.
Though best known as a wildlife artist, he still creates abstract work, showing a major tent-shaped installation at a recent Society of Scottish Artists show in the RSA building. "The two feed into one another," he says. "I hear a lot of rubbish talked by artists from all sectors: unless something's abstract then it's rubbish, or if it's got illustrative qualities, it's without merit. I love doing both. If I was just doing abstract stuff, I would still be sneaking off to do wildlife stuff."
Robertson has painted in Africa, North America, the Caribbean and the Arctic Circle, but his real passion is for the wildlife of Scotland. The day after we meet, he will be up at dawn to head for the Shiants, a group of islands between Lewis and the North tip of Skye.
"I go again and again to places like Handa Island (in North-west Scotland] and the Isle of May (off Fife], and the marshes on the Tay Estuary. The mountains here are fantastically wild and dramatic, and really exotic in terms of wildlife compared with almost anywhere.
"I spend a lot of time being sunburnt, bitten by mosquitoes, rained on, or really cold. I've been chased across fields by bulls. When I was just out of college, I fell about 35ft out of a tree. I was very lucky – I broke every branch on the way down, breaking my fall, but I've tried to avoid climbing since.
"I have a painting of a skua done on Handa which has a fantastic effect at the top because it started to rain into the wet paint before I could get it into my rucksack to keep it dry. Although the weather is really challenging, it's very atmospheric. A lot of paintings I do are about focus, parts of the image are smudged out and left to the imagination. I have a sneaking suspicion that my work is informed by the weather, the way the landscape is continually coming and going."
The flipside of this has been some remarkable wildlife encounters. "I've had badger cubs untying my shoelaces. Badgers have very bad eyesight and one actually ran into me in the dark.
"A couple of weeks ago, I was driving back from Ullapool and stopped at a beach which has great vistas across the Summer Isles and to the mountains of Assynt. There was an otter on the beach and I got quite close to him, managed to do some drawings of him fishing. I was walking back through a landscape of bog cotton, a skylark was singing and I realised I had this huge grin on my face. That's what I'm trying to represent in the painting, seeing something and having an emotional relationship with it, that 'wow' feeling."
The painting on Robertson's easel at the moment, which may take a month to complete, shows a stag in a wintry Highland landscape. "I've got to be very careful: does the deer that I've sketched look like it's the right time of year? Are the antlers the right shape? Is the coat at the right stage of the moult? In the same way that a landscape tells a story, a painting of an animal tells a story just by the way it looks: the time of year, whether it's young, male or female."
Robertson's "hobby" is assisting with wildlife research projects which monitor animal and bird populations and behaviour. Often, he combines this with sketching, but the Aberlady show is a rare chance to bring the two elements together in an exhibition.
The focus of much of his research has been the Tay Estuary's reed beds, a little-known but unexpectedly rich habitat for birdlife. He helped develop a new method for counting the population of water rail, a comparatively secretive bird which resembles a moor hen.
"We knew there were a few there but they're very difficult to see. We developed a way of counting them where we recorded a call, played it back and listened to the calls coming back. For that we worked out that, instead of three or four pairs, there were actually 100 plus, about one third of the population in Scotland at that time. That went on to be adopted as the national standard for counting these birds."
And they found that the Tay estuary was home to the bearded tit, a marsh-dwelling bird with a declining population. "By trapping, ringing and retrapping them, we worked out that a quarter of the British population are on the Tay reed beds, when they weren't believed to be there at all. That study will now feed into management plans for reed beds nationally."
Suddenly, there is a thump. A large grey herring gull has landed on the sill and is tapping on the window with its beak. Robertson says it is pecking at its own reflection, but I think it wants to be painted. It has come to the right place.
• Derek Robertson's Retrospective is at Waterston House, Aberlady, 16 August to 23 October. www.derekrobertson.com