You have to blame something or someone

A Pigeon problem is one factor being investigated in the collapse of the bridge in Minneapolis.

ST. PAUL, Minn. - Pounded and strained by heavy traffic and weakened by missing bolts and cracking steel, the failed interstate bridge over the Mississippi River also faced a less obvious enemy: pigeons.
Although investigators have yet to identify the cause of the bridge‘s Aug. 1 collapse, which killed at least 13 people and injured about 100, the pigeon problem is one of many factors that dogged the structure.