Birds tend to be well insulated so when they fly at altitude in cold weather they don’t lose all their body heat.
The color it appears on infrared footage depends on the other pixels in frame. It uses dynamic ranges to map infrared values to a visible light spectrum. If the rest of the frame was ice, or you were looking up into space, a bird would probably be rendered as very warm.
If the rest of the frame is a warm ocean surface and warm wind turbines, then a flying bird may be rendered as cold relative to those pixels.
Balloons can also show up as a different temperature than the background of the frame depending on what the balloon is made of, altitude differences (ambient temp at high altitude is colder than at the surface), etc.
Could you find some videos for those cases? Would be interesting to see this in action.
Convenient and good infrared video for all these scenarios is hard to come by but would be useful. I think if the DoD was willing to put some money into the budget for practical recreations of UAP scenarios that they then make public, they could do a lot of good. But there'd probably be pushback about wasting money and also risks of leaking information about military sensor capabilities.
But here is a paper showing penguins photographed with a temperature-sensing IR camera, showing the majority of the surface of their body being around -21ºC thanks to the highly insulating plumage.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3645025/
Good find, but I suspect that's quite a rare case - penguins have unique plumage and are also -- ahem, "quite flightless". It might seem I'm splitting hairs (or feathers!) but the "cold white dots" were quite uniform, these cuties are clearly hot/cold patterned - still a good example, bar the flightlessness.
https://x.com/The_Astral_/status/2052922220486205496
Please tell me your feelings on the big picture. I feel it's imbalanced if you provide such certainty to some examples but refrain from a larger perspective. It's okay if you don't want to tho, I just want to know where you're coming from I guess.