Wikipedia: The common English names used are corvids (more technically) or the crow family (more informally), and there are over 120 species. The genus Corvus, including the jackdaws, crows and ravens, makes up over a third of the entire family.
The majority of crows mate for life. Although they reach sexual maturity at age two, many crows don't mate until later - they are waiting for the right partner. Unless their partner is killed, most crows stay with the same mate, year after year.