We chose a simple 0.96-inch LCD display, that is widely available and quite cheap as well. The thermal sensor was more difficult because in order to detect even smaller temperature gradients (23°C outside, a bird might have 25°C), a good thermal and optical resolution would be key - but also expensive, quickly beyond any "reasonable" costs for our project...
Nobody would use this setup to protect animals if it would cost twice as much as an electric Hedge trimmer :-)

The least expensive Sensor we found, the AMG8833 has only 8x8 pixels - and this seemed to be too little. Our best choice then was the MLX9640 which allows 32x24 pixels, 12 times better optical resolution. 

First, we wanted to test the mini display and check on lenses needed, mirrors, and optimal distances for projection:

The next steps included a 3D-Design to fit the display, Raspberry Pi Zero, thermal sensor, and later ideally also batteries - for now, we use a simple powerbank.