The passenger pigeon was a victim of market hunting. Sport hunting had nothing to do with its demise. And further, the passenger pigeon was not hunted to extinction. They had a mating and reproductive ritual that required large numbers in a sort of bird orgy. When their numbers fell below the number require to support their mating ritual they simply stopped reproducing. Market hunters hunted the birds on the nesting grounds by setting huge nets capturing very large numbers at a time. The extinction was accelerated by the precipitous decline in habitat. A contemporary biologist has hypothesized that the passenger pigeon was already on a decline due to other factors and that its extinction was only accelerated by human causation and not completely attributable to humans. They went from billions to extinct in a period of forty years. The passenger pigeon was a food staple for many native Americans. They would hunt the bird's nesting grounds, but would do so after the mating adults had left and would hunt only the young of the year. They were afraid hunting the mating adults would cause them to abandon the nesting grounds. There is an attempt to restore the passenger pigeon by extracting DNA from other pigeons and recreating the passenger pigeon DNA. Some biologists theorize the invasive Eurasian Collared Dove has colonized the U.S. so quickly after accidental introduction because they are filling the niche left by the passenger pigeon.
