Many things look very strange in the infrared but nothing quite so bizarre as ducks. Feathers can hold heat in very well despite being made of keratin which is transparent at the wavelengths of infrared cameras. This must involve infrared engineering at the microscopic level. This image of a mallard shows how effective the feathered areas are for holding the heat in on a cold night. Typically the warm areas are around the head and upper neck that are lightly feathered.
Problems arise when ducks immerse their heads in cold water but show no change to the heat patterns. This video was a filmed on the river Test on a cool May evening but the water temperature is still cold. The duck is unidentified. All birds have strong eye emission but ducks have strong emission sweeping down the neck. Even with oily feathers that prevent water making direct contact with the skin there is still a cooling effect due to radiation and conduction. It is surprising then that there is no cooling effect at all. Is this due to a bioluminescent source that is not sensitive to heat? How is this generated and why? There must be a story here. The bats are Daubenton’s.