Are Birthers part of the Tea party or something totally different?
Are bloggers part of the internet or something totally different?
That's like asking if somebody who's a member of the Masons is a baseball fan. Certainly, one can be both, but the two are neither contingent upon, or exclusive of, one another.
The term "birther" means many things to many people. Some of us simply insist on (verifiable) documentation that Obama is Constitutionally eligible for the office. If he is, so be it; if he isn't let the chips fall where they may (although by application of Vattel, I don't see how he can be).
Rigidly speaking, "Tea Partiers" (Taxed Enough Already) exist to compel fiscal responsibility on the part of the Government in accordance with Constitutional principles and budgetary restraint.