In Korea, magpie(KA-CHI, 까치) means luck. Especially, New Year's eve is known as 까치's new year's day. So, 까치's new year's day is the day before human's.
Actually Korean's new year's day is calculated by moon calendar, not by sun calendar(I know chinese does too). So, this year's new year's day is February 18th. We call this day 설날 SUL-NAL.