Thermal image video of Tree Bee nest
Thermal image cameras are a brilliant, if expensive piece of kit. I use mine as much in the day as I do for my night shooting. They are great for finding nests in dark lofts. Although bees and wasps are cold bloodied insects, they generate a lot of body heat when they fly, so when they come in from the outside they are easy to pick up. The nest itself also generates a lot of heat. Bees leaving the nest are generally cooler than those that have just come in from flying.