The plaintive 'gwarr gwaaar' of two foraging cows is the only sound that greets our arrival at Mt Yarrowyck Nature Reserve, half an hour's drive west of Armidale. The pair swoop and swerve between the stringybarks, keeping a sharp eye on the activities of all who enter the area. More alert than military sentinels, the crows watch over the Aboriginal sites found on the slopes of the mountain. Like us, most visitors to the Reserve are keen to see one of the few publicly accessible examples of Aboriginal rock art on the New England Tableland.