The Birthday is a supporting influence added to the Life Path. Think of it as a modifier to the Life Path. These are traits that you brought into this life much as with the more important and dominating traits shown by the Life Path. Here is your birthday and the modifying traits shown by it:
The day of birth indicates some special talent you possess. It is a gift to you that will help you along your Life’s Path. Your day of birth is one of your four core numbers — the Life Path, Expression, Heart’s Desire being the other three.