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On Aug 7, 2020, at 7:10 PM, Bill Norwood via Phys-l <firstname.lastname@example.org> wrote:
Hi Phys-L Thinkers
I am figuring out why crows are all black.
Perhaps if I write something that DOES make sense, it will combine with the thoughts of others to help explain this black crow phenomenon.
1. Intelligence: Crows are credited with a high level of intelligence:
1a. If a human is hostile to one of them, they will have a meeting where all crows become informed about this particular human, including how to identify the human.
1b. If a crow gets killed on a particular farm, that farm will be avoided in all future migrations.
1c. Crows can recognize individual crows as well as individual human faces.
2. Digestion: Crows are omnivores and are known to eat anything. That would lead to a great variety in energy expended in digesting a particular meal. That would in turn lead to a great variety in how much heat is given off by the digestive system and to a need to efficiently expel heat in the case of a heavy meal. Black would efficiently and quickly expel the heat.
4. Warming and Cooling: A crow finds himself cold standing in a tree, then flies out into the sunlight and quickly becomes warmed, because his black coat is also the most efficient heat absorber. So the crow may have a survival advantage over other birds and small animals in cold or hot climates. Said differently, the crow may be occupying a predatory niche.
Ok, it’s your turn - any ideas?
U of MD at College Park, Physics Dept