I just got my new dove, and it's been really awesome to be around such a beautiful bird, however, I am starting to get worried that she is not eating nearly as much as she should, specially now that I am taking care of a friend's dove and I see her going around the cage eating so much, I am not sure of what do, can anyone offer any advice? I am feeding them both the same food, seeds it is "Alpiste" on spanish, but I am not sure of the english word.

It may be an issue of dominance. Try to separate the birds into separate cages (preferably out of sight to each other), clean the cage, and put in fresh food/water. See if there is a difference. If not, check with a vet.

You said you just got the new dove. How long have you had it? It could very well be a case of it getting used to it's environment. It it's not eating or drinking at all and Michael's suggestion doesn't work, take it to a vet.