Darwin and To Kill a Mockingbird?

Why is the mockingbird a big deal in To Kill a Mockingbird? Atticus Finch tells his kids not to kill a mockingbird because it’s an innocent songbird. In the novel the bird symbolizes the innocence of Tom Robinson and Boo Radley. That’s not all. Charles Darwin discovered that mockingbirds in the Galapagos Islands differed from island to island and the mainland. 

A year after his voyage on the HMS Beagle in 1835, Darwin was puzzled by his notes on mockingbirds. Scientific doctrine said that species were immutable, unchangeable. BINGO!  The different species of mockingbirds proved that species did evolve. The mockingbird metaphor in Harper Lee’s novel is not only a symbol of innocence, but also evolution.  Racists, bigots and cultures can change. Thanks, Darwin.