When I said 'the usual bird vitamins' I was referring to the commercial supplements you find out there which all include minerals (I've never found a single one that had only vitamins and no minerals). But you are correct that minerals are not vitamins and, actually, I should have said 'multi-vitamin/mineral supplement' but everybody refers to them with the shortened version of just as 'bird vitamins'.
And, unless you are referring solely to ingesting betacarotene rich foods, you can definitely overdose betacarotene and we are now beginning to realize that there might be long term adverse effects to oversupplementation. See these:
http://www.wisegeek.com/what-are-the-sy ... erdose.htm
http://www.nutri-facts.org/eng/caroteno ... ne/safety/
This link has a list of all the publications of studies on betacarotene over-supplementation:
http://science.naturalnews.com/B/Beta-c ... ancer.html




