At this time of year the stags' antlers are growing in preparation for the rutting season. While this is happening, their antlers have a soft fur-like covering which carries the blood which enables the antlers to develop, and the stags are described as being 'in velvet'. The rate of growth is rapid, up to an inch a day.
This picture of a stag in velvet, silhouetted against the sunset, comes from Kilchoan Early Bird, to whom many thanks.
For an earlier Diary entry with more details of antler growth, click here.