Thermal is easy, depending what you select in the setup, you are dealing with a profile like "white hot" lighter is then hotter objects. so any mammal / coyote / bird etc will look whiter / lighter in the image, trees / foliage are typically cool and will be dark.
the bird on a wire will be very white against a black-cool sky.
*its very rare you get conditions where ground and or air temperature exceed body temp. but it is conceivable, I have a couple times experienced ground-out when california desert ground were 98deg ish and humans were invisible on the ground basically. but most of the time, specially at night, anything breathing will be hotter than the air. = white profile. (feathers don't show just the naked heating body shows)
*** BTW another thing about thermal, air is an insulator, so long range thermal is kinda impossible as the heat signature become less and less the further the distance.. you should see effective recognition out to maybe a couple hundred meters.. but not miles.
There are exceptions to that, I have seen military equipment demonstrated that product HD thermal images over miles, but this is not true for equipment most of us can buy with disposable income.. so to speak.
Hope this helps, I dont have a thermal scope but with with thermal in general.
