They have now won their last three Premier League games and have moved to within three points of Everton, who they meet in their next game.
This was another comfortable win for Villa which they carved out with first-half goals from the ever-improving Ashley Young and striker John Carew.
Both players were also on the mark in the second half to complete the destruction of a ravaged Blues side, who may now be unable to come back from this humiliating defeat.
Although Mikael Forssell pulled back a goal for Birmingham, high-flying Villa completed their comprehensive win with a fifth strike from Gabby Agbonlahor.
Poor Birmingham were under a cloud even before the game began following the Bolton victory at Middlesbrough which took them out of the bottom three and dropped the Midlands club into the relegation area.
It was obvious that Birmingham sadly lacked the dogged determination of Damien Johnson and Seb Larsson.
As a result they found themselves under considerable pressure from the start as Villa attempted to dominate the 152nd local derby.
It was rare that Birmingham could get onto the attack and their only real effort came when David Murphy fired over the bar.
Villa were always prepared to attack with Carew just heading wide and a Gareth Barry free-kick to the top far corner of the net was pushed away by Maik Taylor.
Stiliyan Petrov, who is at last beginning to show some top form, powered in a shot which bounced off the chest of Taylor.
Villa's pressure had to be rewarded despite Birmingham's stout resistance and in the 29th minute a badly mis-hit shot by Olof Mellberg bounced across to the unmarked Young to lash a tremendous right foot shot to left of Taylor.
Young, who switched constantly between either wing, had another impressive game for Villa and Stephen Kelly, the only outfield player in the Premier League to have played every minute of every match this season, had a hectic time against the young English international.
To their credit Birmingham battled bravely and Mehdi Nafti had one solo effort, which deserved a better reward than a rising shot over the bar.
But Villa could not be pushed back and another raid ended in Taylor being forced to make a diving save to his left to keep out a Barry shot on the run.
Two minutes before the break Villa sealed their third successive win when a Young free-kick deep on the left was deftly headed home by an unmarked Carew for his eleventh goal of the season.
Carew was again on the mark in the 53rd minute when Young put Barry clear to provide a low cross from the right which the big Villa striker, completely unmarked, was able to strike home.
A rampant Villa could not be held and in the 63rd minute Young completely hoodwinked Kelly and jinked inside to fire in a shot which Taylor could only block. Young knocked home the rebound.
Substitute Forssell notched Birmingham's 68th minute goal after taking a return pass from a disappointing James McFadden.
But Young set up Villa's fifth which was scored by Agbonlahor, who beat off a challenge from Kelly to leave Taylor stranded once again.