That dark mohawk isn't just for laughs - it can spike up when the bird is spooked. At first I thought it was some kind of avian secondary sex characteristic, but it turns out both males and females have them. Steller's jays, like many bird species, actually mate monogamously for a long time. Maybe the mohawks help foster communication between old married couples (honey, would you mind watching the eggs while I go find us some insects?).
One of Darwin's main inspirations for the theory of evolution was careful observation of Galapagos finch adaptation. Whether in science or life, I suspect that most of the big lessons we learn come from studying something small carefully and for a long time.