So far, my rat hunting expeditions in my back yard have proven fruitless for me. I think I'm not staying up late enough...before I go to sleep though, I've been setting up a rat trap and baiting it with black oil sunflower seeds. I've caught one rat per night for 3 nights that way. I have a new tool to add to my toolbox though. I borrowed a FLIR camera from work. I think this might help me.

It works quite well I think:

The camera isn't too expensive either, though this model does require an iPhone 5/5S, $150:
http://smile.amazon.com/FLIR-ONE-Thermal-Imager-iPhone/dp/B00K0PXFB6/ref=sr_1_2?ie=UTF8&qid=1438968552&sr=8-2&keywords=flir+one
The newer version will work with anything newer than the iPhone 5, $250:
http://smile.amazon.com/FLIR-Thermal-Imaging-Equipment-Devices/dp/B00VILVV62/ref=sr_1_1?ie=UTF8&qid=1438968552&sr=8-1&keywords=flir+one

It works quite well I think:

The camera isn't too expensive either, though this model does require an iPhone 5/5S, $150:
http://smile.amazon.com/FLIR-ONE-Thermal-Imager-iPhone/dp/B00K0PXFB6/ref=sr_1_2?ie=UTF8&qid=1438968552&sr=8-2&keywords=flir+one
The newer version will work with anything newer than the iPhone 5, $250:
http://smile.amazon.com/FLIR-Thermal-Imaging-Equipment-Devices/dp/B00VILVV62/ref=sr_1_1?ie=UTF8&qid=1438968552&sr=8-1&keywords=flir+one