Pigeons are now one of the most abundant and widespread species on Earth.

Pigeons are now one of the most abundant, widespread species on the planet, managing to thrive in chaotic cities. They owe their success to an ideal combination of traits, including some that were accentuated by humans. Unlike birds that nest on the ground or in trees, pigeons were originally cliff-dwellers. City buildings mimic their natural habitat. And pigeons set a notoriously low bar when it comes to homemaking. Add some sticks to any window ledge or highway overpass and it's a great spot to raise babies. This unfussiness allows them to live in environments where more specialized species can’t.