Since the Royal Society for the Protection of Birds (RSPB) purchased the extensive Abernethy estate in the Scottish Highlands in 1989, it has reduced the local deer population from 1,000 to 300. "We have lost a few members that opposepposed the decision," says David Beaumont of the RSPB's Scottish branch. "But we could not just sit back and let this habitat be further degraded."

The 12.4 km2 Abernethy estate contains 1.8 km2 of Scots pine forest, or 15% of all such forest left in Scotland today. A burgeoning deer population was hindering the regeneration of the centuries-old pine forest, while overgrazing was also damaging the heather on the moors. The pine forest provides habitat for several bird species, including the Scottish crossbill, the capercaillie and the black grouse.

The deer cull has clearly been effective. "Now we see regeneration of the trees out into the moorland, and we can already observe a huge increase of certain bird species," says Beaumont. "This year we have 90 black cocks, double last year's figure. In the rest of the country they are declining." However, the RSPB has no desire to eradicate the local deer population. The deer is a natural part of the pine forest ecosystem, but the population level was simply too high.

The RSPB is dependent on funding from its membership, and had to win their approval before proceeding with the cull. "Most of our members live in the south of England," says Beaumont."They do not have a concept of what it is like to manage an estate in Scotland. We had to explain everything very carefully." But the decision met with little criticism, even from animal welfare groups, and the Scottish Society for the Protection of Animals was actually involved in the decision-making process. Meanwhile, the stalkers responsible for the cull have all attended a training course set up by the Red Deer Commission, and Beaumont believes they have achieved a high level of competency. "As a conservation organisation, we feel obliged to see that the cull is done in the most humane and efficient manner," he says.

The most controversial part of the RSPB's estate management plan was to tear down all the fences erected to keep the deer out of the forest, because an unacceptable number of black grouse were flying into them at night and killing themselves. Sceptics had said that, without the fences, the benefits of culling deer would be cancelled out by a "refill" of deer arriving from neighbouring estates. But this has not happened, says Beaumont, because the hinds are "hefted", or drawn towards, the place where they were born.

Beaumont concedes the RSPB will have to hunt deer on a regular basis if it is to control the population. The deer's only natural predator, the wolf, has not been seen in Scotland since the 18th century, and "it is not on our agenda to get the wolf back."