No one should litter cigarette butts, yet various birds in Mexico City seem to be using them to line their nests because the nicotine repulses a parasitic mite. It is astonishing to consider the intelligence involved in this avian behavior. But this also illustrates how practically all fauna and flora try to adapt to environments altered by humans (or other forces) and use what they can to benefit themselves. I seriously doubt if Darwin would be surprised.
For many years, various scientists have been studying urban forests, the chemical composition of urban precipitation runoff, “heat island” causes and effects, the flora and fauna of cities, and many other urban environmental topics. This is important, for most people live in cities. Scientists, landscape designers, urban planners, and entrepreneurs continue to refine practices that accommodate urban wildlife, lower the “heat island” effect, and even supply city folk with excellent vegetables through community gardens and a growing movement toward commercial “vertical farms” of hydroponic high-rises.
As you might expect, the North American urban environment presents a mixed picture when it comes to fostering and discouraging wildlife. Certain songbirds thrive in the city; others avoid the city altogether. Raccoons and opossums tend to be heavier and larger, feasting on urban diets that often include pet food left on back porches. Deer and turkeys do well, finding lawns and parks conducive to browsing. Even mountain lions and bears move in upon occasion in certain locales, and of course coyotes thrive nearly everywhere, including in suburbs and cities.
I myself have a strange affinity for vacant lots. I like how pioneering “weeds” (more technically, ruderal species) move in en masse almost immediately upon human abandonment or neglect, and how insects and small animals follow. In North America, vacant lots immediately host habitats that feature lifeforms like mosses and ferns, Curly Dock and milkweed, beetles and butterflies. The lack of herbicides in vacant lots actually encourages some native plants, but migrations of domesticated yard species also arrive. It’s interesting how rudimentary food chains immediately appear in abandoned urban spaces. Rats, mice, and birds show up to eat seeds and insects. House cats and foxes arrive to prey upon the smaller animals.
Various scientists have concluded that, overall, urban birds benefit from less predation than their country cousins, despite the perennial hysteria over house cat predation upon birds (just bell the cat, if you’re concerned, but expect an explosion in mice). In towns, suburbs, and cities, we famously fight against mice and rats, but bolster the existence of urban song birds with feeders and birdhouses. Humans are environmental stewards in these circumstances whether we like it or not, and whether we even know it or not.
Nature is resilient. It never goes away, even when cities delude some into thinking otherwise. Rather, urban ecology involves a different array of species compared to farmland, wilderness, deserts, or what have you. Increasingly, Americans are attempting to accommodate nature in cities with things like mountain lion corridors, wildlife-friendly sea walls, phytoremediation to mitigate or even neutralize non-point source pollution, and of course no end of urban forestry considerations to foster wildlife habitat, cool the city, and enhance aesthetics. Some scholars have even studied how urban trees sometimes seem to lower crime rates!
As I wrote elsewhere, “Nature does not abhor vacuums because there are no vacuums in nature.” At least not on planet earth. Urban ecology is a ready example of that.
Copyright © 2022 Will Sarvis. All rights reserved.
Dickson Despommier, The Vertical Farm: Feeding the World in the 21st Century (tenth anniversary edition, NY: St. Martin’s Press, 2020).
Karl L. Evans, “Individual Species and Urbanization,” in Urban Ecology, edited by Kevin J. Gaston (NY: Cambridge University Pr., 2010), 55.
Richard A. Fuller and Katherine N. Irvine, “Interactions Between People and Nature in Urban Environments,” in Urban Ecology, edited by Kevin J. Gaston (NY: Cambridge University Pr., 2010), 136.
Matt Kaplan, “City Birds Use Cigarette Butts to Smoke Out Parasites,” Nature (Dec. 5, 2012).
Stefan Klotz and Ingolf Kuhn, “Urbanisation and Alien Invasion,” in Urban Ecology, edited by Kevin J. Gaston (NY: Cambridge University Pr., 2010), 123.
Stefanie E. LaZerte, et al, “Mountain Chickadees Adjust Songs, Calls and Chorus Composition with Increasing Ambient and Experimental Anthropogenic Noise,” Urban Ecosystems 20 (2017): 989–1000.
Jeremy Lundholm, “Vegetation of Urban Hard Surfaces,” in Urban Ecology: Patterns, Processes, and Applications, edited by Jari Niemelä (NY: Oxford University Pr., 2011), 99.
Robert McCleery, “Urban Mammals,” in Urban Ecosystem Ecology, edited by Jacqueline Aitkenhead-Peterson and Astrid Volder (Madison, WI: American Society of Agronomy, 2010), 87–102.
Sarah L. Robinson and Jeremy T. Lundholm, “Ecosystem Services Provided by Urban Spontaneous Vegetation,” Urban Ecosystems 15 (2012): 547, 550, 551.
Eyal Shochat, et al, “Birds in Urban Ecosystems: Population Dynamics, Community Structure, Biodiversity, and Conservation,” in Urban Ecosystem Ecology, edited by Jacqueline Ait- kenhead-Peterson and Astrid Volder (Madison, WI: American Society of Agronomy, 2010), 75, 76, 78, 79.
James Trefil, A Scientist in the City (NY: Anchor Books, 1995), 8–10.
Matthew F. Vessel and Herbert H. Wong, Natural History of Vacant Lots (Berkeley: University of California Pr., 1987), 1, 5–6, 22, 23, 24.