In dissecting first-round playoff losses by the Bengals, the Lions and the Falcons, the N.F.L. analysts missed the key to the N.F.L. postseason. I learned it two years ago while staring into the comfortless swill at the bottom of my pint in Park Slope, Brooklyn.

The Eagles had lost another playoff game — another Donovan McNabb disappointment, another sequence of baffling Andy Reid play calls. The regularity of their failures made it all seem like fate. A Cowboys fan, laughing in my direction, offered this gnomic bit of wisdom: “If there’s a wing — no ring!”

It took a while to ponder, but then I understood. Regrettably, it’s not about X’s and O’s, or which team drafted well or signed the highest-priced free agents. The secret of the N.F.L. is not calculus or Einstein theory (as the musings of Jon Gruden suggest). It is something more Seussian: teams in the bird family cannot win the Super Bowl.

My mind raced to refute this aphorism. Ah, the 2001 Ravens. Checkmate, Cowboys fan!

But the more I explored, the more it seemed true. The 2001 Ravens are the only fortunate fowl to have won the Super Bowl. They are the exception that proves the rule.