Analysis of Similes For Two Political Characters of 1819

I.
As from an ancestral oak
Two empty ravens sound their clarion,
Yell by yell, and croak by croak,
When they scent the noonday smoke
Of fresh human carrion:--

II.
As two gibbering night-birds flit
From their bowers of deadly yew
Through the night to frighten it,
When the moon is in a fit,
And the stars are none, or few:--

III.
As a shark and dog-fish wait
Under an Atlantic isle,
For the negro-ship, whose freight
Is the theme of their debate,
Wrinkling their red gills the while--

IV.
Are ye, two vultures sick for battle,
Two scorpions under one wet stone,
Two bloodless wolves whose dry throats rattle,
Two crows perched on the murrained cattle,
Two vipers tangled into one.