A biologist was asked to finally determine whether crows and ravens are really two different birds. This has been a matter of some conjecture for quite some time. Given only a cursory glance, these birds appear to be one and the same.

The biologist spent considerable time watching the birds in their habitat and logging hours of observations. The observations did not appear to provide any conclusive evidence that crows and ravens are different.

The biologist performed dissections of ravens and crows and found that their internal workings appeared to be similar. No significant difference was found.

The biologist then performed very careful examinations of two live birds. One a raven and the other a crow. The heads and beaks are remarkably similar. The size and shapes of the birds' bodies did not show much difference. Even the legs and feet of the birds were similar.

But, at last, a breakthrough. The long feathers at the tip of a birds wings, the pinion feathers, provided the conclusion that ravens and crows differ. A raven has four pinion feathers and a crow has five pinion feathers.

The difference between ravens and crows is a matter of a pinion!