A group of deer, including a fawn cute enough for Disney, graze peacefully among the trees, unperturbed by the pouncing cheetah barely 10 metres away. Over at the small loch, a heron is motionless by the water's edge while a prehistoric-looking iguana evolves from the water. Among the trees by the burn, you can spot a cluster of plovers and scattered solitary scaffinches.

The art of Helen Denerley works in many settings. Those giraffes (properly entitled Dreaming Spires) at the top of Leith Walk in Edinburgh are her largest works to date, while much earlier pieces of hers are still to be admired on the Devon Way foot and cycle path through the Hillfoots villages of Clackmannanshire. Oystercatchers grace a corner of the campus at nearby Stirling University, while sheep, ducks and hens make a farmyard of the new Duloch Park shopping centre in Dunfermline.

Beautifully crafted from her cache of scrap metal at home in Clashnettie in Strathdon, Aberdeenshire, Denerley's animals are instantly recognisable and appreciated as much by connoisseurs of sculpture as they are loved by the general public. Maintaining that balance is important to the artist. "I hope I never have to make a choice between making work for private collectors and public commissions," she says. "Not everyone can afford art and it is important that people still have access to it."

In fact, the range of scale in the pieces she makes is not only a crucial element of the charm of the work; it means they are affordable, too. Her smallest birds, those "scaffinches" with gilded plumage fashioned from Yale-type keys, are £250. If you have the resources, a camel will set you back a hundred times that.

It is the Ship of the Desert that greets visitors to one of the largest ever exhibitions of Denerley's work, currently to be seen at Gleneagles house by Auchterarder, the home of Petronella and Martin Haldane. This show of work for sale has been two years in the making, and dates from the couple's purchase of one of Denerley's sheep for their own collection and their support of the charity Hope and Homes for Children, which will benefit from a percentage of the sales.

The setting for the show is not just a matter of display. Denerley has made two-thirds of the works - and there are nearly 60 pieces - for the exhibition space of the Haldanes' garden at the head of the glen. That iguanic dinosaur is an older piece, but the herons were made specifically to occupy their locations on the loch. A chubby red duck squats in a channel over which viewers have to step to complete their circuit of the water, while cousins of those Stirling oystercatchers stand on the rail of a bridge. A pair of swallows perch on a fence and the scaffinches are on the arms of various benches.

Nearer the house, lazy dogs lie near the lawn and a peacock struts by the woodstore. Less identifiable birds, with serated plummage like sci-fi creations for Doctor Who, stand sentinel on a path, while that cheetah, Denerley's most recent creation, stalks the long grass. Rarely is an art show quite such an adventure to view.

Look closer and the works are a singular mix of form and function. The oystercatchers share basic form in the sumps from BSA motorbikes, those three letters clearly embossed on their bellies. The cheetah is also assembled from discarded motorcycle parts. A bovine beast in the garden, entitled Sacred Cow, is of more fascination to farmers, agricultural machinery identifiable in parts from hoof to horn.

Denerley trained at Gray's in Aberdeen and the college's continuing commitment to excellence in drawing is detectable in the clean lines of her finished work, as well as in the sketches she makes en route to the sculptures. "I was attracted to working with metal straight from school, but I couldn't do it without drawing," she says. "I saw shapes in scrap, and everything I use brings its own story with it."

On the opening weekend of the exhibition, Denerley's narratives were already proving popular with purchasers, with work commanding five-figure sums (including that splendid big cat) selling as readily as the smaller pieces. That's good news for Hope and Homes for Children, which tries to unite young people in war zones with their families or enable them to rebuild their lives, and benefits from a committed support network in Perthshire.

There may, however, still be some works to be claimed - and the show is worth a visit just for the opportunity to see such a menagerie of Helen Denerley sculpture in such an exquisite setting.