There are a few reasons the passenger pigeon was brought to the point of extinction. Market hunting and over-exploitation were the primary culprits. Because their flocks were so gigantic, firearms, nets, clubs, and poles were used to quickly harvest thousands of pigeons at a time. The invention of the telegraph and railroad transportation across the country allowed humans to quickly locate roosting areas for harvesting squab (i.e., young pigeons), and trees were often cut down to gather them easily. Railcars literally full of pigeons would leave for larger markets daily (PA Game Commission 2010). Forests full of food sources were replaced by agriculture and other developments. After decades of diminished reproductive success (called recruitment), loss of habitat, and direct mortality, the population reached a tipping point from which it couldn’t recover.

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