Warning about photographing of vultures

We have had some problems at our feeding site at Giants Castle where photographers are attaching wires to bones and nailing these in the ground so that the birds don't remove the bones/meat from the site while they photograph them. The larger birds, particularly bearded and cape vultures are pulling the nails out of the ground when they grab the bone and are flying off with them. Since bearded vultures swallow bones, they will probably swallow the nail and wire with the bone which could cause major injuries.

Please would photographers desist from these practices. The attached poster should be circulated to all bird clubs etc. - For the Vulture's sakes.