In David Attenborough’s documentary episode “Cities” in Season 1 of Planet Earth: II, a number of species are featured to illustrate how they have adapted to the rapid changes posed by urban cities. Urbanization has led to the destruction of natural habitats of many species due to increased human activity, pollution and noise, all of which offer very few favorable conditions for wildlife .
Feral pigeons are descendants of wild rock pigeons, Columba livia, that have successfully adapted to the rapid urbanization of cities. Throughout cities, buildings and window ledges act as artificial habitats that simulate the rocky cliffs and ledges found in the wild. Studies have shown that wild pigeons have retained some of their ancestral foraging strategies by eating leftovers from lunches found on the streets, plazas, parks, docks, and subways underpasses .
The documentary takes a closer look at the adaptability of wild pigeons on the streets of Aldi, France. Studies have shown that pigeons in urban settings have lower flying heights than pigeons from rural environments . The intraspecific difference shows that pigeons that grow up in an urban environment have a greater tendency to live closer to or on the ground. In addition, they are often spending time near well populated human areas or near rivers. This suggests that urban pigeons have increased risk-taking behavior tendencies. However, this increased risk-taking behavior of urbanized pigeons poses a new danger. The Wels Catfish detects oil from the pigeon’s plumage and devours the pigeons as prey . This is peculiar because the usual diet of the catfish does not consist of pigeons. Interestingly enough, the Wels Catfish has proliferated within the Parisian waters and virtually exterminated local fish stocks, consequently developing a taste for pigeons.
Humans beings are part of the earth’s ecosystems. Over the course of rapid industrialization in the past decades, rock pigeons have modeled how once the equilibrium of the ecosystems is disturbed deliberately or inadvertently, organisms must adapt to survive. Yet at the same time, new dangers arise while organisms try to adapt to their changing environments. This suggests that other organisms may co-evolve at the same time.
by Daniel Won and Bill Zheng
Planet Earth II, “Cities” (Season 1, Episode 6), starting at 36:13
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