Above: Flight tests (cloudy daylight, ~3 pm winter afternoon)
FLIR image taken by conservation drone from ~100 m above ground. FLIR camera tilted ~40 degrees downwards.
NEC image taken by conservation drone from ~100 m above ground. NEC camera was downward facing.
Ground tests (complete darkness, ~9 pm winter night):
The FLIR is the clear winner in terms of picture resolution and thermal sensitivity. But the FLIR HS-324 is also much heavier and costly (~600 g, ~US$ 7,000) than the NEC (~300 g, US$ 4,000).
Based on these tests, we believe the ideal solution might be the more compact FLIR MS-324 (320 x 240 res) (link), which has the same resolution as the FLIR HS-324, but weighs much less (340 g) and is also more affordable (~US$ 3,000).
(*Note: We are not sponsored by the companies hyper-linked to in this post. The cameras we tested were either rented or on loan from colleagues.)