I couldn't find any bass tabs
for this song.So I made my own 
for my band when they play it.

enjoy

Blackbird...
G[---------------
D[---------------
A[---------------
E[-3-3-3-3-8-8-10 x2

Everybody wants...
G[--------
D[--------
A[--------
E[-0-0-8-8 x3

Maybe be your...
G[----------
D[----------
A[-0-0-0-0--
E[---------8 x2

So when does...
G[--------------
D[--------------
A[--------------
E[-3-3-3-3-3-3-3

Cause I'm gonna...
G[--------------------
D[--------------------
A[--------------------
E[-0-0-0-0-0-0-0-0-0-0

I just wanna be...
G[------------------------
D[------------------------
A[-0-0-0-0-0-0-0----------
E[---------------8-8-10-10
then repeat the top tab during the harmonica part 


lyrics:
black bird slow and softly breaks a glass of wine
broken bluesy whispers sing to me tonight
well everybody wants to go forever
I just wanna burn up hard and bright
I just wanna be your firecracker
Maybe be your baby tonight
Maybe be your baby tonight

radio kicks the silence off into your room
kiss me slow and softly make me dream of you
well everybody wants to go forever
I just wanna burn up hard and bright
I just wanna be your firecracker
Maybe be your baby tonight
Maybe be your baby tonight

So when does the plane go down
cause I'm gonna ride til' it hits the ground
I'm going down with a fight
I just wanna be you baby tonight