Ravens were once a rarity in the North Country, but now they are becoming a common sight. They have a similar appearance to crows, but if you see the two birds together the difference is obvious. For one thing, ravens are big. For another, crows caw, while the cry of a raven is more of a croak.Martha Foley and Curt Stager discuss other ways to tell the two apart, why ravens became a scarce presence in recent times, and why they might be making a comeback now.