The wind on Crow Hill was her darling.
His fierce, high tide in her ear was her secret.
But his kiss was fatal.
Through her dark Paradise ran
The stream she loved too well
That bit her breast.
The shaggy sodden king of that kingdom
Followed through the wall
And lay on her love-sick bed.
The curlew trod her womb.
The stone swelled under her heart.
Her death is a baby-cry on the moor.
The  curlew  is a bird of northern climate with a distinctive cry.  One myth is that it represents souls waiting to be born.  Cathy dies in childbirth. Emily had no children but “gave birth” to one of the greatest novels in the English language. 
 The idea that the bird “trod” her womb is violent and disturbing. 

Emily Brontë