Hi Nicholas, When i first started to bait field mice and voles for food for my little owl project i tried all sorts of methods but i then managed by accident to find something that attracted them, i know you want to photograph them and not bait them but it could still work,when i purchase live mealworms i put them in a tub with rolled oats (food for the mealworm and insulation in winter) when i was putting the mealworms out for the birds their was always a scattering of oats that always ended up on the floor and i found that sitting in my hide waiting for the bird i spotted voles and mice had been attracted to the oats ,and i would always see at least one ,sorry for going on but basicaly what you could do is find a area not far from you thats cat free and pretty quite and basicaly try to bait them ,its amazing what turns up,you may have to spend some time keep going back and hoping you spot signs that they have been but it can be done , its all about food association with the area you pick...no doubt someone could help with a better food source for attracting them ,but my left over oats certainly worked .