The first time I realised how dependent I had become on thermal scanners was over a year ago when I accidentally left mine at home on a cold December evening. The first week I got my scanner I had started taking it with me when I walked my dogs at night, where it was deployed as an expensive poop detection device. So I had left it on the side with their leads and not taken it stalking. The minute I realised I didn’t have it on my neck, a sudden feeling of emptiness set in, as if I had lost my car key or my mobile phone. I had a capable pair of 10x50 binoculars on me but why did I feel so unprepared for my stalking session?