not really. a small gift. American think that is just a way the employee shows respect to their boss. Usually when your birthday comes, the boss will give a small gift to you for return shows the boss also care about the employee. Don't image too much. Because before i gave her the birthday gift, i asked my coworkers.
That is why I said my former boss even wanted to give me a birthday gift because one week before my birthday she asked me " will i be in the office on my birthday?''.