I love birds. Mostly the smaller ones. Oh, I know the snowy egret is a wonder, but cardinals and bluebirds just make me smile as I start my day.
Recently, I came across a research article on the brilliantly colorful Tanagers, who make up fully 10% of all songbird species. Anyway, a graduate student, Nick Mason, at the Cornell Lab of Ornithology wanted to see if Darwin's theory that brightly colored birds don't have
complex songs and dull colored birds are singing divas was accurate. He decided to look at the hugely diverse Tanagers by measuring the plumage of 303 species using a spectro-photometer and analyzing 2,700 recordings of bird songs.
The research team studied nine feather color variables and 20 song variables to develop a “complexity” score for both plumage and sound. Mason used the Macaulay Library of bird songs (world's largest/oldest scientific archive of biodiversity audio and video recordings) for his research.
When the feathers had settled, the team found that there weren't widespread limits on the evolution of showiness vs. singing.
So contrary to what Charles Darwin speculated, birds, or tanagers at least, can be "beautiful and mellifluous, or drab and hoarse, or anything in between."