budgie attacking budgie

Question
QUESTION: I saw a question asked by somebody previously about female budgies.  I have a similar problem, except that my budgies are males and the response to the previous question was specific to female budgies.  I have two in a fairly large cage and they have lived in relative harmony for a few years, with only an occasional squabble over food.  Suddenly one of them has started to attack the other one viciously, chasing him all over the cage.  They ended up at the bottom of the cage with feathers flying and a lot of screaming.  I separated them and put the aggressor into an old cage that I had in the basement. My question is whether you know anything about this behavior.  What could cause this change after years of peaceful coexistence?
Thank you.

ANSWER: Females are almost always more aggressive than males.  There usually isn't really any reason for it.  I would give it a week or so in solitary confinement, and then try putting them together.  Once you put them together, I'd put in another food dish to keep minor squabbles from turning vicious.  

They may well resume a more peaceful coexistence.  My friend has a breeding pair, and the female almost killed her mate once; since then they've had eight babies!

Give them time, she may grow out of the habit.
I hope this helps!
-Leah

---------- FOLLOW-UP ----------

QUESTION: Dear Leah
I did not ask about females.  My two budgies are males, which was the point as you had already told somebody that females are more aggressive BUT MINE ARE MALES.  There is also two of everthing in the cage and every time we give treats (in addition to regular food), we put two of the treats in the cage.  The question is, do you have any idea what would cause this aggression after years of getting along?  thank you.

Answer
Sorry about the mix up, I should have read the question more carefully.

Normally males coexist very peacefully.  There is sometimes competition over mates, food, that sort of thing, but its probably just a behavioral issue in your case, considering they got along for so long.  What sometimes works is taking a spray bottle of slightly warm water and once they start fighting, spray the aggressor (it tends to work better if you use it on the stream setting, rather than the fine spray).  This doesn't always work, because many birds love water, but it can be effective in getting the fight to break up.  Its a form of discipline that is harmless to the birds and often effective.

Again, sorry about the confusion and giving you a useless answer.  He might just grow out of it just as soon as it became an issue.  

I hope this helps!