The Spanish colonies wanted to be independent for quite some time, and they just waited for suitable moment when the Spanish army would not be at its best, sot hat they can rebel and gain independence. The situation in Europe was going in the advantage of the Spanish colonies, as Spain was distracted by war, with Napoleon conquering pretty much everything on the continent. As most of the Spanish army was deployed to defend the homeland, the troops in the colonies were significantly weakened. The people in the colonies were monitoring the situation carefully, and when they saw that the Spanish army is weak enough, they attacked, managed to push them away, and gained independence one by one.
