I know it's not this one, but this is very evocative. Clearly it's not about a blackbird!
The Bird and the Tree
By Ridgely Torrence
BLACKBIRD, blackbird in the cage,
There’s something wrong tonight.
Far off the sheriff’s footfall dies,
The minutes crawl like last year’s flies
Between the bars, and like an age
The hours are long tonight.
The sky is like a heavy lid
Out here beyond the door tonight.
What’s that? A mutter down the street.
What’s that? The sound of yells and feet.
For what you didn’t do or did
You’ll pay the score tonight.
No use to reek with reddened sweat,
No use to whimper and to sweat.
They’ve got the rope; they’ve got the guns,
They’ve got the courage and the guns;
And that’s the reason why tonight
No use to ask them any more.
They’ll fire the answer through the door—
You’re out to die tonight.
There where the lonely cross-road lies,
There is no place to make replies;
But silence, inch by inch, is there,
And the right limb for a lynch is there;
And a lean daw waits for both your eyes,
Blackbird.
Perhaps you’ll meet again some place.
Look for the mask upon the face:
That’s the way you’ll know them there—
A white mask to hide the face.
And you can halt and show them there
The things that they are deaf to now,
And they can tell you what they meant—
To wash the blood with blood. But how
If you are innocent?
Blackbird singer, blackbird mute,
They choked the seed you might have found.
Out of a thorny field you go—
For you it may be better so—
And leave the sowers of the ground
To eat the harvest of the fruit,
Blackbird.