My view:
Avilculture: Fun but probably difficult to use as a stable source of income
Tax prep: Good potential, though seasonal. A CPA may be required, but often is not (a CPA is requird when working on a corporation's tax returns, but not for individuals or businesses functioning as sole proprietorships; check IRS and your state regulation for details). Add to that general business accounting and bookkeeping and you have a potential annual market.
Latin translation: Extremely difficult, though there is a paying market for Latin translation, mostly of things like university diplomas that are in Latin, but must be translated for licensing or other purposes. This is a very small market, so like aviculture, probably fun but not a good source of income.
Someone I know makes money doing bookkeeping and payroll for local businesses. He has a B.A. in economics (no CPA or other certification). A friend is a CPA and puts that to good use. I'm a translator and in my 15+ years in the field have met a couple of people who have been paid to translate Latin (I have too, BTW) in the form of the small jobs I mentioned above. I know nothing about birds except that my cats like to watch them.