It’s not just the birds who’ll be flying south this winter. A Newbury Street landmark is heading that way too. To the South End, that is. Stephanie’s on Newbury — the iconic Back Bay spot for weekend brunch and some of the best people-watching around — is slated to open a second location in December or January at the corner of Tremont and Union Park, adding another stellar option to the bustling South End dining scene. We expect Stephi’s on Tremont (571 Tremont Street, Boston) to be like Stephanie’s younger, more laidback sister, thanks to a 66-seat dining room, outdoor patio, bar with three widescreen televisions, and the kind of sophisticated comfort food Stephanie’s has been serving up for nearly 15 years. Stephi’s final menu is still in the works, but we can’t imagine that executive chef Corey Comeau won’t include the beloved warm goat cheese appetizer or the grilled cheese on brioche from the original Stephanie’s list. This year, there’s a reason to get excited about old man winter rolling in.