Many astute historiphiles will be aware that the capitol of Massachusetts was once the intellectual nexus of early American society. Indeed, one look no further than Ye Olde’s Tourisme Boarde’s 200 year-long campaign that advocated the state motto “Braintown! Population: Knowledge!” Reveling in the glut of famous writers and artists they lived in close proximity with, 19th Century Bostonians drank themselves dizzy while quenching their curiosity with the dank brew called “Knowledge.”
What is less known to storytellers, professional and amateur alike, is the source of this wisdom. In fact, it is now clear that this wellspring of enlightenment sprang from the Magnificent Thunderbirds. These wise and powerful creatures once freely roamed the skies of New England, meting out equal parts divine justice and bird shit. Possessing arcane knowledge of science and philosophy, they benevolently ruled the proud Native American people.  
Benevolently, however, until the coming of the White Man. Claiming that they were conscientious objectors, the Thunderbirds instead welcomed the Europeans with open wings. They never flagrantly involved themselves with these interlopers until the American Revolution. It was not the French, an intangible sense of liberty, or the icy Russian tundra which stayed the enslaving hand of the wicked British Empire. Agreeing to aid this fledgling nation if certain tribute was paid, the Thunderbirds tore through the weak and puny Redcoats like so many earthworms and grubs.
The tribute was to be an offering in massive quantities of the following: actual grubs, delicious worms and an infinite amount of cranberries. It is because the god-appeasing cranberries grew best in the swamps and fens of Massachusetts that the Thunderbirds made their home in Boston.
In the seventh period of the Tweetel bird-era, Skwakus (9th Bird-Lord of the Quackemet dynasty) made his home in the Boston Common. A regular sight for the average Bostonian was too see Skwakus copulating in mid-air with any number of elegant, sensual members of his royal harem. However, an average Bostonian (let’s call him “Harold Allbright”) would not turn away in church-indoctrinated shame. Rather, Harold Allbright might say to himself, “Harold, old boy, you ought to be thankful for them wonderful Thunderbirds! Why, without that arcane knowledge they gived us, I can only imagine the sad state of affairs that we’d be in!”
Harold Allbright would be right.
When the War Between the States erupted in South Carolina in 1861, the North began its steady march towards victory. Alighting on the path this march would take, a spry Abraham Lincoln dusted himself off and assessed the situation.

September 14, 1861
Dearest Fraulein Messerschmit:
My darling, I ache willingly for you. To return to our love-nest in Prussia is my only desire. But first: I must rescue this accursed country from auto-erotic asphyxiation.
I am aware that the North’s main strategic and material advantage lays in our undoubtedly wide margin in the field of brain-stuff. We are so in excess of science, philosophy, art and literature that I feel we may embarrass those Dixie fuckers simply by arriving on the battlefield.
I must consult with Skawkus. Our need for arcane knowledge and twigs has never been higher.
Much love,
Abraham “Chain” Lincoln

However, old Honest Chain wasn’t the only person who realized the gap between the intellectual prowess of the North and that of the South. Confederate president and Hindu mystic Jefferson Davis also felt the pressing need to address this disadvantage.

November 23, 1861
Dollmer:
All praise is due to Shiva, God of Destruction and Spiritual Repair.
Schedule a meeting with Admiral Gacy and Field Marshall Koenig. I must send a secret U-Boat to Massachusetts in order that we learn the arcane knowledge of the Magnificent Thunderbirds.
Sincerely,
Jeffy D. (President of the C.S.A.)

One week later, Davis sent a secret U-Boat to Massachusetts in order to learn the arcane knowledge of the Magnificent Thunderbirds. Led by Captain Felder Beck (and secretly monitored by Confederate Agent Ninja-san Bylaw), the crew of the CSS Go-Bot met with Lord Skwakus. The timing was fortuitous. The Thunderbirds, grown slovenly by constant gorging on cranberries, sought a challenge. Skawkus hoped that war would boil the avian blood of the birds of his feather and infuse it with passion once more.                
At the moment the audience with the Bird-Lord was concluded, the Murder Flock was dispatched. Soon, all of Boston was pummeled from the sky with mystical explosives and bird shit. Terror had free reign in the Hub of the Universe, and soon the nation would crumble.
While Jeffeson Davis was reclining in his executive office (probably smoking a cigar while chuckling contentedly, pausing only to periodically sip from a snifter of brandy) to contemplate the subjugation of a capitalist empire by mud farmers and racists, Union Intelligence was scrambling to use the remaining (and quickly dwindling) arcane knowledge to respond to the Thunderbird threat.
Unsurprisingly (because Boston is wicked smart), a solution was conceived of at the Massachusetts Institute of Technology. Graduate student Nate Stormont called upon his knowledge of the natural enemy of birds: cats. Stormont (whose PhD thesis was entitled “Occident and Mendel: The Rending of Genes in Pursuit of Increased Kitty Aggression) was studying feline breeding when he conceived of the Omega Were-Cat. With federal funding, the future Dr. Stormont took twelve black, long-haired Manx and created deadly feral beasts.
With the Omega Were-Cats roaming Beantown in the darkness of night, the Thunderbird population was thinned and eventually eradicated. Soon (as we well know) the South collapsed under the weight of its unique brand of slavery. Or something.
The Omega Were-Cats would have to be eliminated, as fish supplies around the city plummeted. Fortunately, Dr. Stormont created the Cerebus Dog Corps. After leftovers and dog shit began to appear at an alarming rate, the Mailmen of Sorrow were created. Which is why the mail is always on time.