Surprisingly, lighter plumage isn't necessarily better in hotter climates.
Tell Crows & Ravens Apart — Corvid Clarity
Raven vs. Crow: What's the Difference?
How to Read Birds as Omens and Signs - Exemplore
Common Raven - ID, Facts, Diet, Habit & More
Are crows bigger than ravens? - Quora
Ravens with funny tufts of feathers on the sides of their heads. (Got your bill by Canislupuscorax.)
Crows: Everything you need to know about the whole corvid family, from ravens and jackdaws to rooks, magpies, jays and choughs - Country Life
Crow curiosities: what causes white feathers?
13 Raven Facts To Unveil The Mysterious Bird
The Mystery of Crows with White Feathers