Our relationship with the rest of biodiversity

Lessons from birds, from humans, & from the peculiar world of suburbia

Written by Nick Minor

Edited by: Katherine Hill, Sienna Schaeffer

Imagine you live in a house, situated in one of America’s many quaint suburbs. It’s a winter morning, and all around the house, it’s quiet. Save the soft hiss of the occasional passing car and the tinkling leash binding a dog to its walker, the day is lulled under a heavy blanket of quietude.

But as the morning grows and warms, the sounds of life, as fearlessly profuse as ever, tear through the blanket. Around your house are a diversity of shrubs and native grasses, each beneath trees representing a total number of species that would surprise you. Gradually, a chorus of avian callnotes ring out from amongst these plants, even in their leafless, winter dormancy. House Sparrows, of course, but also House Finches and Northern Cardinals. A roving flock of robins flies in to gorge on the crabapples across the street, an endeavor in which they are soon joined by Cedar Waxwings. The occasional woodpecker swoops onto the massive silver maple in your neighbor’s yard — sometimes a Downy Woodpecker, sometimes a Hairy, sometimes a Red-bellied. If you look closely, the woodpeckers are sharing the maple’s peeling bark with a winter visitor, the Brown Creeper.

The morning goes on, and through your yard and the surrounding area marches a steady parade of different bird species, each engaged in a perpetual search for sustenance. A Cooper’s Hawk flies through the yard in search of the bird feeder’s slowest visitor. Some Canada Geese fly over, having taken off from a nearby lake in search of fertile soy fields, that are soon followed by quick-flying group of courting Mallards. A Red-tailed Hawk soars over, riding the thermal uplifts that the sun, uninhibited by clouds, powers across the landscape. Dark-eyed Juncos and even a Song Sparrow feed around the edges of the snow covered lawn, mindlessly hopping over deer and rabbit tracks that were laid in the cover of last night’s darkness.

And the parade goes on. Each species, foraging for its particular food in its particular way, is part of the local community. Through this richness of winter species, a surprisingly complex and multifaceted food web is created. The links in the web affect the populations of every bird you see — not to mention all the other non-avian species present.

Indeed, if humans are cast as the world’s biodiversity destroyers, suburbs suggest that we may be failing miserably.

That’s not to excuse the atrocious loss of irreplaceable biodiversity in the tropics through rampant deforestation. Nor does it make right the filling of the oceans with waste, the excesses of a throw-away society, or the everywhere-changing ecosystems in an age of anthropogenic climate change.

But too often, these problems — and indeed those whose lives are directly affected by them — are distant from us. Many of us in American suburbs have experienced life in a way that has been climatically unchanged since the first sirens about climate change started going off. Even if we do agree that climate change is an issue, and express a desire to do something about it, one can’t be blamed for forgetting about the issue when it appears so far off from the suburban way of life.

But above, in the quaint suburban backyard, we saw something that was close. In spite of humanity’s ability to destroy ecosystems, sometimes we erect new ones. New ecosystems that, while heavily altered, can be surprisingly diverse. And sometimes, if we play our cards right as nature-lovers and amateur landscape managers, these ecosystems can also be stable and can flourish.

As people who care about biodiversity, it is here that we should start. Many of us forget that there is a biologically rich ecosystem in most of our backyards. Species are already adapting to a human-altered world, one complete with buildings, concrete and pollution. While some species lose in the new world, clinging on in marginal pristine habitat, others adapt or even exploit the new world. With suburban humans often comes a profusion of new plant species, each carrying their own nutritionally unique fruits, and each supporting their own community of insects. Humans bolster bird and mammal populations with food: bird feeders and compost piles. They even introduce ideal shelter plants — like Arborvitae or blue spruce — as an extension of their aesthetic preference for landscapes.

Sure, humans also bring pesticides and fungicides. They bring fast-moving cars and invisible windows. They bring wild cats and aggressive invasive species. They bring disruptive light and distracting noise. And a lot of the time, humans’ negative influence outweighs the positive.

What we must remember is that none of these negative influences on local ecosystems are things that we do inherently: we can choose to act differently. We can choose instead to do as much as we can to enable a profusion of biodiversity around our homes. As homeowners, we have immense influence over a small area of land, and we can do a lot of good with that influence for the non-human species that share it. And as one home greens its surroundings, homeowners around them will take notice and perhaps even follow suit — humans are a social species, after all.

You might be asking, “What are some things I can do to have a positive influence?” How can we better coexist with the biological communities around us? John Marzluff, an ornithologist at University of Washington, wrote a beautiful, succinct, and timely answer to this question, now published as Welcome to Subirdia. In it, he opens by revealing just how great the biodiversity of suburbs can be, often greater than nearby swathes of pristine habitat. He closes with the provocative “Ten Biodiversity Commandments,” which we would all do well to live by, be it in cities, in suburbs, or in rural settings. Below, the commandments are reproduced, with explanations to follow:

#1 — Do not covet your neighbor’s lawn

As far as biodiversity goes, one could be forgiven for calling lawns a “green desert” (to be honest, deserts don’t even deserve this metaphor — they are often surprisingly rich landscapes in spite of their aridity). Worse, the maintenance of this desert costs Americans around $30 billion a year, much of which is wasted in the 17 million gallons of lawn-mower gas spilled each year. You read right — 17 million gallons is more than the amount spilled at Exxon Valdez, and is as much as was spilled at Deepwater after 12 years.

Additionally, American lawns are sprayed with 7 billion tons of water, 3 million tons of nitrogen fertilizer, and 30 thousand tons of pesticide every year. Not only is this green desert ecologically empty, but it is also one of history’s most expensive landscapes.

What can we do to foster more biodiversity in our lawns and to save a little money? The so-called “Freedom Lawn” is one possible solution. Designed by professors at the Yale School of Forestry and Environmental studies, the concept sets out to increase yard biodiversity by taking the following steps:

• reduce the extent of turf
• border that turf with shrubs
• shade it with trees
• mow with hand- or electric-powered mowers, and do so much less often
• increase plant composition all around
• leave dead trees, thickets, brush piles, rocks, and logs
• Look for local certifications for such a lawn

Why the certification, you ask? All of these changes come with a social dimension. In this case, neighbors could misunderstand, seeing lawn neglect instead of habitat restoration. Certifications help in two ways: they show that instead of being neglect, your lawn is deliberate, part of a mission to pave out a more sustainable future. Second, they connect you to some truly admirable, typically local organizations.

#2 — Keep your cats indoors

Behind the veneer of cuteness, it turns out that feral cats are the major limiting factor of wild birds in urban and suburban areas: 1 in 10 wild birds living near humans are killed by cats. Those that persist suffer lower nest success and higher exposure to lethal cat-borne diseases like toxoplasmosis.

This issue is so widespread — yet so under-discussed — that Pete Marra of the Smithsonian Migratory Bird Center recently wrote a book about it titled “Cat Wars.” Doesn’t get much clearer than that.

Luckily, this issue has an easy remedy at the scale of the individual property-owner: keep your cats inside.

#3 — Make your windows more visible to the birds that fly near them.

Window collisions, especially around our homes, closely follow outdoor cats as a source of bird mortality. On average, each residence in the United States results in 2 to 4 collision-based deaths per year. These range from death-on-impact to subtle brain injuries that, combined with the many challenges of surviving, lead to rapid deterioration. Annually, this amounts to around a quarter of a billion collision-based deaths around our homes alone, not counting the number of birds that collide with skyscrapers and other large towers.

Unlike step #2, solutions to this problem are a little more complicated. Glass can be modified to become bird-friendly by adding etchings, decorative frostings, or even simple stripings: the American Bird Conservancy’s “Bird Tape,” when spaced 4 to 6 inches apart in a window, almost entirely prevent bird collisions.

While those at the frontlines of wildlife preservation will be sure to adopt these solutions, most people won’t be drawn to unsightly stripes across their beautiful living room window. Worse yet, the somewhat aesthetic falcon decals plastered on many a-window are mostly ineffective; in Marzluff’s words, “the goal is for windows to be visible, not scary.”

Instead, the solutions to this problem come up in the process of building construction and landscape design. Window glass, for example, is being developed that is covered with ultraviolet lines, making it highly visible to birds (who can see ultraviolet-range light), but clear to humans. Such bird-friendly glass can be chosen when designing new buildings or installing new windows.

Landscape design has much to do with window collisions as well — if coniferous trees that birds shelter in, birdbaths, or bird feeders are close to large, non-bird-friendly windows, you can bet on many collisions!

#4 — Do not light the night sky.

Perpetual light is a facet of urban and suburban existence; where there are people, there will be light. While this makes life easier for us, it is highly disruptive to species whose activities once only occurred in the dark.

Prominent among these activities is the vast ocean of bird species that migrate north and then south every spring and fall. The majority of North America’s long-distance migrants conduct their journeys at night. This way, the birds are safe from most predators and can spend the daylight stuffing themselves with protein-rich invertebrates.

Like human sailors, these birds navigate in part using the map of the skies, reading the stars for a sense of orientation. Drawn to certain stars’ light, they have been a feature of the shifting seasons for millions of years.

While these navigational instincts have served migratory birds well for most of their history, artificial light has turned them into a liability. It seems intuitive that light from cities would help diurnal birds to see the landscape and navigate more accurately; if they navigate using sight, don’t well-lit cities help? Here, that we need a little context: birds have had to adapt to dark skies over millions of years, and they have done so admirably. But the very adaptations that make the dark manageable are confused when exposed to too much light. It’s like the disruptive effect of a camera flash in a dark room. Lighting vast urban areas at night makes some of birds’ navigation senses unusable and others untrustworthy.

Light pollution around human developments blocks out many of the stars that the migrating birds once used to find their way. Worse, birds are disoriented by or even drawn to particularly bright light sources. Their other navigational senses — like their ability to detect the earth’s magnetic field — are particularly disrupted by red and white light. The end result is more than 7 million bird deaths per year caused by artificial light-based disorientation.

The solutions, like with our homes, require foresight, and sometimes local political action. All of the following are first steps that are within every urban resident’s grasp:

• Give local political support for shutting off your city’s more ostentatious lights at night
• Use night lighting as sparingly as possible. Keep in mind that bluer lights are the most disruptive, while yellow lights are the least.
• Sometimes, warning lights are necessary, be they on large cell towers or around airports. Still, blinking the light often suffices, and they needn’t be colored the more disruptive red or white.
• Around your home or beyond, advocate for outdoor lighting that faces down, not out. Horizontal lighting is a major source not only of light pollution, but of wasted energy.
• Join your local Lights Out program!

#5 — Provide food and nest boxes

When feeders are available, birds use them to supply around 20% of their dietary needs, indicating that feeders are useful but not absolutely necessary to wild birds. Feeder birds, then, are not an army of dependents — they are an array of fully wild animals whose diet and well-being is bolstered by feeder food, not replaced by it. In addition to this primary benefit, birdfeeders connect people to local birds in an intimate way, and bring billions of dollars into local businesses annually. There’s a lot to like in the simple practice of feeding birds.

To attract the most birds, consider the following information:

• To appeal to the most birds, go for black oil sunflower seeds and white proso millet.
• To increase avian diversity in your backyard, supply nectar for hummingbirds; thistle seeds for goldfinches and Pine Siskins; peanuts for nuthatches, chickadees, and titmice; whole popcorn kernels for pigeons (the wild kind) and doves; and suet for woodpeckers.
• Keep your birdfeeders clean and dry. If you’re not careful, feeders can be better at spreading bird diseases than at nourishing them.
• Let the feeder go empty now and again. This forces birds to feed on and help disperse seeds from other seed-producing plants in your yard. Not replacing feed mimics the uncertainty of resources in the wild, keeps rodents at bay, and makes cleaning easier.

Nest boxes, like feeders, are a simple way to bring more birds into the yard, but they have a different ecological history. In essence, bird nest boxes exist to make up for the lack of naturally occurring tree cavities. As such, it is best to put nest boxes close to other plant shelter. Ultimately, leaving some dead branches or even full dead trees in the yard is far better than providing nest boxes. If it’s not a hazard, the breeding woodpeckers, songbirds, or even Wood Ducks may be well worth the eye sore.

#6 — Do not kill native predators

Like any ecosystem, the ecology of your yard will be more stable through time when some predators are present. Predators provide your backyard ecosystem with checks and balances, helping to stem the spread of disease and cull the unsustainably abundant. This ecosystem service just isn’t something we can provide ourselves, or at least not at natural levels. Feral cats may be a predator we could introduce, but as we saw above, the prey mortality extends far beyond what can be sustained by native bird populations. Similarly, poisons can help reduce overly-abundant species, but not without degrading or decimating populations of other, unintended victims (think Red Foxes, Bobcats, or Coyotes).

What we need then is a guide forward for coexisting with predator species. Below are three simple steps that lead to a coexistence that is more peaceful than fearful:

• Do your best to dispose of garbage and compost correctly.
• Keep small pets inside so as not to offer them as prey.
• If you use pesticides at all, do so to an extremely limited extent. While they may help your plants along, the ripple effect of pesticides in the rest of the ecosystem are often not worth the initial effort.

#7 — Foster a diversity of habitats and natural variability within landscapes.

In Marzulff’s words:

Variety, not uniformity, should be the rule.

Birds, mammals, reptiles, amphibians, invertebrates, fungi, and plants themselves benefit from “diversified” turflands. Replacing a landscape of grass with a landscape of native ground, shrub, and tree cover opens more ecological niches, provides rich and varied shelter for other organisms, and in general hosts a greater diversity of species. All great things that come from a simple shift in landscaping philosophy.

But wait, there’s more! Even without the influence of humans, the community of native species in a given region often differs significantly from the community in another region. Designing landscapes that follows this trend, with unique mixes of plant species in different regions, fends of biotic homogenization, which is the process by which different regions’ species communities become more similar. This homogenization tends to favor only a few species that can acclimatize to just about anywhere with human influence on the landscape — not the species that make that region unique.

Diverse, regionally unique landscapes, then, are a worthy goal that one can easily aspire to on their own property.

#8 — Create safe passages across roads and highways.

Birds in temperate regions tend to be pretty good at dispersal, remaining able to cross barriers like busy highways. But in the more tropical ecosystems close to the equator, birds become less adept at crossing such barriers. Worse, reptiles, amphibians, and mammals, which lack the advantage of flight, have generally fared poorly in the face of road development, regardless of their location.

We live in a world crisscrossed with over 40 million miles of highway, most of which are in automobile-dependent countries like the United States. Roadways passing through areas of undisturbed habitat — be it virgin forest or native prairie — would benefit greatly from so-called wildlife over- and under-passes. These passageways allow wildlife to disperse through highways without any risk of destruction-by-car. See here for an example of these wildlife crossings designed for Mountain Lion conservation.

Like with light pollution, this commandment comes down to local political advocacy; if a wildlife crossing project is proposed in your area, make your voice heard and support it!

#9 — Ensure that there are functional connections between land and water.

Building on the principles of the commandment eight, number nine applies them to the whole landscape. Landscapes are the theater for all of nature’s diverse activities, ranging from human development to animal migrations. Ideally, human development and activities are planned in such a way that they minimize any disruption of other species’ activities. Of course, this ideal is often not met, but the disruption need not last forever. In many cases, the damage is not irreparable.

Even within a city, forward-thinking and ecologically conscious urban planning can reconnect blue and green spaces that non-human species depend on without sacrificing convenience for people. Many urbanites know their local examples well — the park systems of New York City, Boston, or the Chicago lakefront. These so-called “Emerald Necklaces” reestablish fundamental connections between sub-populations of species and regional species pools, allowing individuals and their genes to flow freely through the landscape.

We must not forget the benefits these “Emerald Necklaces” hold for humans. Greenspaces provide stress relief, natural resources like clean air and water, aesthetic pleasure, cooling effects, and urban noise reduction. Whether your advocacy is best placed in a small neighborhood board or in proposals to a city government, that’s something from which we — and many other species — would benefit.

#10 — Enjoy and bond with nature where you live, work, and play!

This commandment, in spite of the vast scale or applicability of those above, is probably the most important. Urban and suburban citizens in the United States experience a paucity of ‘nature’ in their lives. On average, Americans spend only 5% of their day outside. While some may not notice the effects of such a small amount of time outdoors, many authors (like Richard Louv or Florence Williams) have coined terms for this malady like “nature deficit disorder” or “environmental amnesia.” It leaves us more anxious and more self-absorbed, and less able to concentrate or think creatively (see citation 2 at the end of this piece for more on this). But beyond the effects on the individual, our disconnect with the natural world is a symptom of a more fundamental cultural and philosophical problem, which has its roots in early in American history.

Since the beginning of American environmentalism in the late 1800s/early 1900s, conservationists like John Muir and Theodore Roosevelt have argued for the value of preservation, or setting aside areas of ‘nature’ to be left pristine and untouched: wilderness. Certainly, preserving undeveloped land is important, providing habitat for more sensitive species, and providing an awe-inspiring safety valve for people. But at the risk of offending those who support all of the above ideas, I would argue that this conservationist modus operandi may do more harm than good.

Why? Because it assumes a dichotomy between humanity and nature: here, in ‘unnatural,’ artificial environments (like cities) live humans; out there, in wild places, lives nature. While the spiritually transcendent experiences we have in the wilderness may leave us strongly in favor of preservationism, this human vs. nature thinking has two fundamental problems, the first being philosophical and the second being ethical:

1. It may well be impossible to draw clear lines between what is and isn’t ‘natural.’ After all, humans evolved like the rest of biodiversity, and humans use natural resources to do everything we see as ‘artificial.’ Why, then, are human cities, technology, or other developments less natural than, say, a beaver’s dam? And besides, doesn’t the very fact that humans set aside areas of wilderness make them somewhat artificial? If human-caused climate change is affecting all of the earth’s ecosystems, doesn’t that imply some artificial manipulation of even the most remote wildernesses?
2. By believing nature is something that is out there, the rest of biodiversity and undeveloped landscapes fall victim to the out-of-sight, out-of-mind effect. Nature is no longer personal to us, no longer close to us, and instead becomes abstract and far-off. We lose our sense of place in nature, making it less relevant to our day-to-day lives. Because conservation work depends on what a culture values, it’s no wonder that conservationists have to resort to only saving charismatic species like tigers and polar bears: people have simply lost sight of the protection-worthy biodiversity all around them. As a result, we unconsciously accept lower environmental standards, persisting in hot and dirty cities that need not be.

Wilderness preserves are important and necessary, but their critical flaw stems from the very fact of their being set away from people: most people will never experience them, and therefore, will never care personally about them. If people don’t have access to or recognition of the ecosystems around them, conservation — especially local conservation — may never get the support it desperately needs.

Along with preserving remote and sacred wilderness, we must become aware of and conserve the biodiversity all around us. This broader conservation ethic helps us not only to recognize but also to care about the cardinals, the House Sparrows, the Rock Pigeons, the chickadees, the robins, and all the other adaptive species that are often closely associated with human development.

Best of all, greener, more biodiverse cities and suburbs provide one more thing in life to relish and to support in our gardens, our parks, and our waterways.

~

Ultimately, doing these things on one property may not have much of an influence. But like with anything worth doing, we must start small. We must work with what we have, and make the best of it. Having done that, we can only hope that others around us will be empowered when we explain what we’ve done. Because, after all, the only way to correct our negative impacts on the Earth’s other species is to get our hands dirty making positive impacts, no matter the scale.

Let’s get to work.

Citations:

Marzluff, John M. Welcome to Subirdia: Sharing our Neighborhoods with Wrens, Robins, Woodpeckers, and Other Wildlife. New Haven: Yale University Press, 2014.

Urry, Amelia. 2017. “Anxious, Depressed, Distracted — What If The Cure Is Just Outside?”. Grist. Accessed March 8 2017. https://grist.org/living/anxiety-depression-and-distraction-what-if-the-cure-is-just-outside/.