Out our back doors, animals and plants are doing amazing things and communicating and interacting via means we are only beginning to understand, as Nancy Lawson, the founder of The Humane Gardener, explains in her new book. Nancy returns to the podcast this week to discuss this “Wildscape” and how research is uncovering the surprising ways that human activity interrupts the natural world.
Nancy blogs at HumaneGardener.com and previously worked for the Humane Society of the United States as a magazine editor and vice president of content. She became interested in gardening and native plants during her time with the Humane Society and continues to write a column on ways we can be friendlier stewards of land for the Humane Society’s magazine, All Animals. She published “The Humane Gardener: Nurturing a Backyard Habitat for Wildlife” in 2017, and just last month released “Wildscape: Trilling Chipmunks, Beckoning Blooms, Salty Butterflies, and other Sensory Wonders of Nature.”
Nancy has been a writer ever since she was a little kid, which explains why she’s so good at it. It’s fascinating just how much Nancy is able to write just from what she has observed in her own yard, and she brings in relevant stories from around the world to help explain the wildlife behaviors she’s noticed.
I love the way Nancy sets the stage in the introduction to her book:
“Your outdoor surroundings are a vibrant universe, a place where many languages are spoken, sometimes in sensory alphabets we humans have hardly even begun to decipher. It’s swirling with hidden messages: ephemeral molecules spelling out an invitation or piecing together a cry for help. Ultrasound clicks you can’t hear and ultraviolet colors you can’t see. Calls of alarm, distress, defense, and companionship that reach your ears but require a translator to decode.
If you treat the local environment like the homeland it’s meant to be, you’ll be exposed to more cultures and ideas and ways of life than if you visited with people from every country in the world.”
There is so much right outside our backdoor and our front door if we just take the time to stop and look and listen, and as gardeners, we need to be more aware of how we’re encroaching on the habitat of the creatures we coexist with.
“Your space can be different once you stop trying so hard to defend its borders and start looking at the world from the perspective of other beings who live there,” Nancy says.
Before proceeding any further, I’d also like to pause to remind you that I also have a new book out, “The Vegetable Gardening Book: Your complete guide to growing an edible organic garden from seed to harvest.” This book has insider tips and new-to-you information that will help you step up your gardening game and tackle challenges.
Gardening for Wildlife Senses
“I’ve been complaining about things like leaf blowers for decades now, and I think my friends just were putting up with it for a while until it finally got so chronic for them too,” Nancy says.
It took a while for people to catch on about how damaging leaf blowers, lawnmowers, string trimmers and other machines with loud engines can be to wildlife. “More people understand now,” she says.
It was her husband, Will Heinz, a cancer scientist, who gave Nancy the idea to write a book not just on noise and hearing, but on all five senses. There are all these books about gardening for the human senses, like fragrant flowers and night-bloomer flowers, so, he suggested, why not write something on gardening for wildlife senses?
Nancy says Will understands her need to explore and learn everything about a particular thing because he’s also very curious about a range of topics.
“There are so many organisms that we’ll never even know are there, that haven’t even been studied, that no one knows even exists, even in our own spaces,” Nancy says. “And the ones we do think we know, we really don’t.”
In researching her book, she observed animal behaviors that she figured someone must know something about and the reasons behind them, but she discovered that, in some cases, no one’s asked the question yet.
“It’s just sort of like an ongoing mystery that hasn’t been funded for studies,” she said.
But something positive that Nancy learned is how many discoveries individuals can make by exploring their own yards and habitat.
“You don’t have to be an expert in a given area,” she says. “You kind of become an expert by exploring and reading and asking questions. And science tells us so much, but science only knows so much. And so following your heart, your intuition, mingling the two, I think is really important to a better understanding of the world around us.”
Butterfly Frass Flinging
Martha Weiss, Georgetown scientist who Nancy spoke to for her book, had studied silver-spotted skipper caterpillars, which also shoot their frass fast and far. Weiss told her that the caterpillars do so to avoid predation by northern paper wasps.
Nancy was watering some new plants she had planted when she saw a little fritillary caterpillar eating a violet. She got down to take some pictures and video, and then that’s when she noticed a bulge going through the caterpillar’s body and then it shot out a green bit. Fortunately, she had captured the moment on video, so she could play it back in slow motion and share what she had seen. One Instagram follower pointed out that there was already evidence of a tiny wasp on the fritillary caterpillar, as well as a hyperparasitic wasp on that wasp.
In this one sighting there was a hall of mirrors of more and more predatory relationships, Nancy says. And this is just one example of how insects use their excrement to hide from predators.
Nancy spoke to an ecologist in Wisconsin who studies one-spotted tortoise beetles (Physonota unipunctata) on their host plant, wild bergamot (Monarda fistulosa). “It has very interesting scents,” she says of wild bergamot. “It’s very herby.” The beetles, in their larval stage, use their frass to make shields on their backs.
Nancy says since the frass is plant waste, it probably smells like the wild bergamot the beetles had eaten. That can throw off predators that follow the scent trails of prey.
The fairly new field of odor pollution is uncovering how human activity is disrupting scent communications that insects and other creatures use.
Some chemicals that are naturally scentless to humans are purposely infused with a smell so we’ll know that they have been applied. For insects, that applied scent can inhibit their life cycles and behaviors.
A number of other scents from human activity, such as diesel exhaust and fertilizer, are affecting insects in ways we are just beginning to understand. And in the presence of fungicides, bees can’t learn floral scents, Nancy says. Some scents just confuse bees and mask floral odors, and others actually pull the other odors out of the air, so bees can’t find flowers, she adds.
This “signal jamming” may also affect mammals and birds, though more research is needed. It used to be that researchers believed birds and frogs, for instance, didn’t have a sense of smell, or didn’t rely on it. “Now we know differently,” Nancy says.
“There are general themes we can infer from all of this about going more gently on the land — it’s always going to be better,” she says. “There are certain things that we know are sort of like guaranteed habitat enhancers and so we do need more studies, but in some cases, we don’t. We just need to have more common sense.”
To identify where it needs to be, a butterfly uses completely different organs than we do, namely its antennae and feet. Its antennae help it locate plants from a distance, and its feet tell it if it has indeed landed on the right plant.
Nancy has observed fritillary butterflies land on violets — their host plants — and lay eggs quickly. She has also seen them land on plants that look kind of like violets, such as young mistflowers, and quickly take off without laying an egg. So while sight alone is helpful, it’s unreliable, and that’s where the feet come in.
The sensory environment has only gotten louder and louder with man-made noise. Noise pollution irritates us humans and also affects birds, frogs and other wildlife.
Quantifying the effects of man made noise on people and animals is difficult. We know how noise from acute noise sources like chainsaws can damage our hearing, but measuring stress from chronic noise such as traffic is not as easy.
“Around the world, migratory birds are avoiding noisy areas,” Nancy notes.
In our backyards, Project FeederWatch observed common birds like goldfinches are avoiding noisy areas.
Owls and bats are foraging less because the noise masks what they need to hear, and researchers have also observed fewer bluebird and tree swallow eggs hatching.
In San Francisco, during the pandemic when the traffic level was reduced to nearly nothing, white-crowned sparrows could be heard again, and they were able to sing in a broader frequency, Nancy says. “That could possibly affect their mating; it could affect how their competitors see them if they’re not able to sing in their natural broad range.”
Another researcher who Nancy interviewed studied field crickets and the parasitoid tachinid fly that preys on the crickets. The researcher played traffic noise in a field with crickets. “The tachinid flies could not find the crickets anymore,” Nancy says. The noise masked the crickets from the flies, which have great directional hearing but could not overcome the traffic noise.
These flies are a natural control of cricket populations, Nancy explains. When that control is removed, cricket populations grow, and those crickets prey on plants — devastating the plant population.
In another study, monarch butterfly caterpillars exposed to traffic noise began biting the researchers. And in New Mexico, a study found that near noisy natural gas compressors scrub jays were no longer disbursing seeds, leading to far fewer trees in those areas.
In her book, Nancy describes the “tastescape” as a sensory feast with sweet moments such as a cardinal teaching its fledglings to forage while taking frequent breaks to feed them, or a mother deer and her fawn reuniting for a nursing session, but also a treacherous place where the need to feed starts wars among plants and animals.
Understanding the tastescape can help us become more conscious gardeners.
Nancy explains how aphids on milkweed weaken the plants and reduce their defenses in a way that makes it easier for monarch butterfly caterpillars to eat them. And when milkweed plants are populated with various insects, there is a “dilution effect,” studies show, that leads to monarchs being left alone by parasitic wasps and predators because there are more insects available to eat.
Reasons to Love Chipmunks
Some animals are using every single part of the land and they know every inch of it, Nancy says. Chipmunks are her favorite example of this. They are not only eating the nuts of trees and using the leaves in their burrows, but they are also making their burrows in the root system of fallen trees.
Chipmunks plant trees by burying nuts and seeds, and they, like voles and mice, are moving mycorrhizal fungi around. Nancy says it was researcher Ryan Stephens who realized how important of a role they play in dispersing fungi.
“People get so upset with these animals for eating plants, but they’re actually nurturing plant growth too with their activities,” Nancy says.
I know there are a lot of chipmunk haters out there, though I am not one of them. They might reconsider their position if they knew the benefits of having chipmunks around. The fact is there are probably benefits and drawbacks for everything on this planet, but we only see what we want to see sometimes.
HOAs and Native Gardens
For gardeners who raise native plants and practice ecological gardening, living under the strictures of a homeowners association can be frustrating, to put it mildly.
Nancy had helped her sister, Janet Crouch, to introduce native and pollinator-friendly plants to her property in Maryland. Then in 2017, Janet’s HOA sent a letter telling her she needed to remove “weeds”
“She called me and was like, I can’t believe this because their garden is beautiful,” Nancy recalls.
They wrote back that they removed a few weeds, like patches of Japanese stilt grass, and explained that it was a humane garden and designed for birds.
Nancy says in a subsequent letter the HOA lawyer wrote that a planned community is “no place for birds” and that her garden attracted squirrels, mosquitoes and snakes. Ultimately, Janet got to keep her garden and got a state law passed barring HOAs from requiring turfgrass and prohibiting pollinator gardens.
“She got on the board,” Nancy says of her sister. “She did all the things that you could possibly do to fight for this for three and a half years.”
The New York Times wrote an article about the episode, titled “They Fought the Lawn. And the Lawn’s Done.”
Among the creative chapter titles in “Wildscape” is “Costume Parties,” referring to the camouflage insects use.
Nancy’s friend is gifted at spotting emerald moth caterpillars, which cut off pieces of flowers and stick them onto their bodies to hide from predators. Nancy knew the caterpillars like Echinacea and black-eyed Susan, so she went looking for them herself — and found them. She observed a sweat bee come along and bump into a caterpillar without realizing it was there. Even more impressive is that the caterpillars redo the camouflage each morning.
If you haven’t already listened to my conversation with Nancy Lawson on the wildscape, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
Do you have plantings or whole gardens dedicated to wildlife? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
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joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
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The Humane Gardener – Nancy’s blog
“The Humane Gardener: Nurturing a Backyard Habitat for Wildlife” by Nancy Lawson
The New York Times: “They Fought the Lawn. And the Lawn’s Done.” by Cara Buckley
All Animals magazine
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Corona Tools, Milorganite, Soil3, Greenhouse Megastore, Territorial Seed Company, Earth’s Ally, Proven Winners ColorChoice and Dramm. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.