Woodpecker vs. cactus … an age-old battle. In the last line, the reader needs to switch the accent to the last syllable on “paucity” to make the rhyme come alive. A favorite ploy of mine. 

The red-belly’s bill rapid-fires amidst, 
A burnt Sonoran reach, and 
Into the stem of a lone cactus, 
Whose thistles dint the prickly heat. 
Yet although the saguaro is teethed, to 
Dissuade a woodpecker’s siege,  
‘Tis a careful joust that he accepts, 
To tap its cache of rich insects, 
    In this stretch of dry paucity.