Harper Lee's "To Kill A Mockingbird" was a prescient novel. Rooted in the civil rights era of the 1950s, it could also be set in modern-day America, where bullies versus innocents and democracy versus autocracy are inherent. These two birds are distinguished by their personalities, and this novel's symbolism of them reflects the human condition, which is as germane today, as it was in 1960, when it was written.
To Kill A Mockingbird's bird references . . .
The longest quote about the book's title, and the bird references of the blue jays versus the mockingbirds is cited in Chapter 10, pg, 119:
“Atticus said to Jem one day, "I’d rather you shot at tin cans in the backyard, but I know you’ll go after birds. Shoot all the blue jays you want, if you can hit ‘em, but remember it’s a sin to kill a mockingbird." That was the only time I ever heard Atticus say it was a sin to do something, and I asked Miss Maudie about it
"Your father’s right," she said. "Mockingbirds don’t do one thing except make music for us to enjoy. They don’t eat up people’s gardens, don’t nest in corn cribs, they don’t do one thing but sing their hearts out for us. That’s why it’s a sin to kill a mockingbird.” (ch. 10, pg. 119)
Symbolism of the Birds represents teachable moments . . .
The blue jays are autocrats. They represent the racism and injustice of the world. They're the senseless bullies who display careless and evil behavior. They don't tolerate other birds being around. They are physically aggressive, in chasing and attacking all birds that enter their territory.
Not communal in nature, when they mark trees to nest, they will forcefully fight against any other bird that enters their borders. They're thinking is not determined by individuals. They're controlled by the mob. Think about how the blacks were segregated in the 1950s, and how migrants from Mexico and Central America are treated today, where an autocratic leader construct a "wall" to block out "the other."
Mockingbirds, on the other hand, are democratic. They're a passive bird always defending itself in nature against bullies (ergo bluejays). They represent innocence. While mimicking the sounds and songs of other birds, they do so to protect their turf. When they are free from threats, they generally sing their melodious songs.
Scientists believe that mockingbirds imitate the calls and songs of other birds to discourage these birds from settling in the mockingbirds' territory by making it appear to be heavily populated. The mockingbird's vocal cords, called the syrinx, can produce a wide variety of sounds and songs of others.
In most instances, unfortunately, the blue jay is the victor. They most often triumph over the mockingbird in any backyard brawl. Bullies not only want their own turf, but they also want it all.
While we could venture a guess as to why Ms. Lee named her protagonist "Atticus Finch," which is the makings of a blog for another day. Suffice to say the main character of this novel is the rational arbitrator who defends innocence against evil. That Jem and Scout’s last name's are also Finch (another type of small bird) indicates that they are particularly vulnerable in the racist world of the 1950s, which treats race harshly, similarly to how racism continues to exist in today's society, where a bully rules with a swift and unruly hand -- one that favors autocracy over democracy.
“You never really understand a person,” Atticus says, “until you climb into his skin and walk around in it.” It's a simple premise on the surface, but one that's complexed as the natural world where birds of a feather may not all be allowed to flock together.
Primary Source: To Kill A Mockingbird