This is a question I’m often asked and like most things in life, very situationally and budget dependant. Looking at likely quarry species in range of size with the hope associated environments will help illustrate points. If you are ratting with an airgun, night vision can open a whole world of shooting possibilities when minimal levels of ambient light from the moon or general farmyard illuminators should give you satisfactory sight picture to take on these numerous rodents. But, beware using strong additional IR illumination from the gun/scope itself as reflections from intervening items or foliage can make the image auto-dim and leave you a little `blind`. Any Quarry in grass and other ground cover can be invisible to the naked eye or even night vision, but with a thermal scope, and not one needing to be particularly expensive, will stand out clearly to make an assured shot. Small quarry is also relatively easy to identify at close ranges and shooting through grass or straw is unlikely to be a problem when quarry is totally hidden, but their body heat always gives them away, under a steel container for example.
Budget is key and when you take a step up beyond similar rabbiting needs to foxing, the protection of livestock and gamebirds is simpler to quantify and justify a larger spend. Given ranges up to perhaps 300 metres, precision shot making is key, but identification is the most important safety factor. After detection of the quarry, easily enabled at extreme ranges with a thermal spotter, the sight can itself be an EMERGENCY STOP tool, having given a different perspective on identification than thermal alone. Night vision, with good IR illumination will show strong details a Thermal will not and although that latter capability is catching rapidly, the ability to see quarry using a second image style can be a great benefit. Night vision is usually much less expensive than thermal, and I personally use a thermal spotter with night vision scope for this very reason, the dual perspectives in a dark environment. The caveat to this is the ground you shoot over, long grass can easily hide quarry which `pops` straight out with thermal and allows you to call it, track its movement and assess its patterns for identification without alerting it in any way.
“Thermal shows you what you want to shoot, night vision shows you what you want to miss” has often been a helpful mantra to me. That IR reflection will often show you a wire fence that would have made your bullet ricochet or heavier cover you cannot simply shoot through. It’s easy to get carried away by a bright white thermal heat source and forget the surrounding details! Neither technology is an outright winner, I see them as complimentary tools rather than competitors. If money were unlimited, high-end thermal for both is an easy option because the latest units have great features and detail recognition but on realistic budget (just like the same rifle/scope budget we have so long worked on), I think maximum capability is available from a thermal spotter combined with night vision scope. The spotter is in use far more often and is the primary stage in identification before you ever even get close to pointing a rifle at your quarry.
By Chris Parkin