For the first time in nearly a half century, puffins are returning to Ailsa Craig, a plug of volcanic rock off the west coast of Scotland. Curling aficionados already know the island as the world's preferred source of curling stones.
Curling is the centuries-old sport in which people slide smooth granite stones across a 146-foot-long (45-meter-long) sheet of ice toward a bull's-eye, trying to knock their opponents' stones out of the way in the process. Stones used in the sport must withstand a healthy amount of abuse and constant freeze-thaw cycles.
About 250 years ago curlers discovered that the granite on Ailsa Craig made perfect curling stones. About 60 to 70 percent of the curling stones in use today are fashioned from Ailsa Craig granite, according to Mike Thompson, the secretary general for the World Curling Federation in Perth, Scotland.
The United Kingdom's Royal Society for the Protection of Birds hopes to make the island as well known as a sanctuary for seabirds as it is for its stones.
The 104-acre (42-hectare) island is home to more than 40,000 pairs of cliff-dwelling northern gannets and is considered a haven for guillemots, razorbills, and other seabirds. Puffins, wiped out by an infestation of rats introduced by quarry workers in the 19th century, are now rebounding, albeit slowly.
Rats were eradicated from the island in the early 1990s, after the British government recognized Ailsa Craig as a Site of Special Scientific Interest, a designation that bestows certain protections.
In 2002 the first puffins returned to the island. Today the population stands at 10 to 20 breeding pairs. In March the Royal Society for the Protection of Birds, a conservation nonprofit, agreed to manage the island as a nature reserve.
Curlers, meanwhile, retain access to the island's valued stones for the foreseeable future. No new blasting is permitted in the quarries once mined for the granite stones. But the quarries remain littered with chunks of rock suitable for carving new curling stones. A manufacturer is permitted to haul them away.
"The main areas of stones for curling-stone interests are away from the most important bird-breeding areas," said Alan Lauder, regional reserves manager for the Royal Society for the Protection of Birds in Glasgow, Scotland.
Curlers prefer Ailsa Craig blue hone granite for the superior running surface it provides. "It is very dense rock that is resistant to water absorption. It's not porous," said Rick Patzke, a spokesman for the United States Curling Association in Stevens Point, Wisconsin.
The dense, nonporous nature of blue hone granite prevents it from easily pitting, said Geoffrey Broadhurst, a curler with the Ardsley Curling Club in Ardsley-on-Hudson, New York. Pits occur when water infiltrates a stone's pores and then freezes. As the water expands, it cracks the rock.
"Until 30 years ago most indoor curling rinks did not have dehumidifiers to reduce frost on the ice. Also, when rocks sat on the ice, moisture would condense on the surface and penetrate into the granite pores. When the moisture froze, the granite would pit … which is very bad for the bottom running surface," Broadhurst said.
Thompson, of the World Curling Federation, said some curling stones are made with granite from Trefor, Wales, but they are more prone to pitting than Ailsa Craig blue hone granite.
"The view of some experts is that in 20 to 30 years time, Ailsa Craig stones will probably last a bit longer," Thompson said. "There are Ailsa Craig curling stones in use today that were quarried 40 to 50 years ago. They have an extremely long life."
No suitable granite has been found for fashioning curling stones in North America, according to Broadhurst.
Today many curlers are moving toward stones that have striking bands—the portion of the rock that bangs into other rocks—made from Trefor granites, which are more durable than Ailsa Craig blue hone granite. The same curlers prefer to use blue hone inserts for their stones' running surface.
Curling garnered significant television coverage during the 2002 Winter Olympic Games, and, as a result, the sport's popularity has surged. The growing interest has increased demand for curling stones, according to Patzke, the United States Curling Association spokesman.
Thompson, of the World Curling Federation, also noted a steady increase in demand for curling stones over the past six years. "Becoming an Olympic sport [in 1998] has been considerably effective. Coupled with that, curling is now appearing on TV today in a way it wasn't done in years gone by."
Six European countries joined the federation in December 2003, and Thompson cites exposure on the satellite-television sports channel Eurosport as the reason for its growing popularity. There are an estimated 1.5 million curlers worldwide.
Both the United States Curling Association and the World Curling Federation help newly formed clubs find used and refurbished stones for their members to throw until the clubs are on their feet and can afford their own stones. It can cost upward of U.S. $40,000 to fully outfit a club with stones.
To keep pace with the rising demand in curling stones, Kays of Scotland, an Ayrshire-based curling-stone company, received permission in 2001 to cart 1,500 tons (1,360 metric tons) of granite off of Ailsa Craig. The company has permission to return to the island on a periodic basis.
Lauder, of the Royal Society for the Protection of Birds, anticipates this relationship working to the benefit of the island's birds and curlers for years to come.