"Pigeon droppings cited in bridge collapse"
                             —Toronto Star

Behold the ***** birds that felled a bridge
Of concrete, iron, and steel routinely made,
Dropping by dropping, pigeon after pige-
on adding contributions grossly laid.
An engineering feat commercial grade,
The bridge could not withstand the pigeon poo,
And, from the scourge of filth, the bridge decayed,
And fell as all decaying things will doo.
(When not creating mayhem, pigeons coo
And congregate and caper in the park,
Returning to their nests—tu-whit tu-whoo—
Before the owl can hunt them in the dark.)  
And so we see the danger we permit
When pigeons are allowed to give a ****.