I agree with others a thermal monocular is the way to go for picking up animals. I've never scanned with just my gun/scope but have friends who hated it after the first 30 minutes and shortly bought a thermal scanner. A handheld monocular is just so much more convenient. Something like an AGM Taipan 384 or iRay Cabin will fit most. As others have mentioned, thermal scopes are great but its a buy once cry once deal. There are ~$2k thermals that will work but you will be wanting to upgrade shortly. I'd say around the $3k mark you can get a good 384 thermal. I've been running a Bering Optics Super Hogster which has fit my needs for the last 3 years and only upgraded to a 640 w/lrf recently.
NV will obviously be a lot cheaper. Pulsar C50's are around $1400 and probably one of the better NV scopes or Rix just came out with the Tourer T20 for $600. I recommend upgrade the IR light for either NV. NV is better for identification as others mentions but with a little time behind a thermal/watching thermal videos its not a problem identifying an animal based on body movement. I went straight thermal from the start and haven't looked back. I'm not a fan of the reflection from vegetation that happens with NV/IR light or if an animal is in beans/grass field it can be difficult at times to find them with NV if they aren't looking at you to get the eye shine.
