Natural imagery dots the landscape of both poems.  Given the topics of each, this is not unexpected.  Achebe introduces the natural conditions that establish the basis for both poems. This imagery can be seen in "Vultures" with Achebe's description of where one vulture sits "perching high on broken bone of a dead tree."  Similar natural imagery can be seen in "Butterfly" as Achebe establishes the natural world of the butterfly colliding with the human world: "But at a crossroads where mottled light/ From trees falls on a brash new highway/ Our convergent territories meet."  In both works, the images of nature are essential to establishing the rising action of each poem.

There is imagery of destruction in both poems.  In "Vultures," this imagery is seen in different parts of the poem.  The description of of the male vulture ("his smooth/ bashed-in head, a pebble/ on a stem rooted in/ a dump of gross feathers") is one such example.  This destructive imagery is enhanced with the imagery of Belsen:

Thus the Commandant at Belsen
Camp going home for
the day with fumes of
human roast clinging
rebelliously to his hairy
nostrils

In these images, organic destruction is an essential part of the poem.  Similar destruction can be seen in "Butterfly."  In the poem, Achebe describes the collision of the human world with the natural one:  "I come power-packed enough for two/  And the gentle butterfly offers/Itself in bright yellow sacrifice/ Upon my hard silicon shield."  The imagery of being "power-packed" and how the butterfly succumbs "upon my hard silicon shield" suggest a sense of destruction.  In both poems, the world that is featured is one where destruction is an intrinsic part to it.  Both poems feature imagery that conveys this destruction, suggesting that there can be no escape from a world where ruination is a necessary part of being in the world.  Achebe ensures that this imagery is not far from the reader's mind.