Beauty of Earth Blog

There was an old man with a beard,
who said: “It is just as I feared!
Two owls and a hen, four larks and a wren
Have all built their nests in my beard.”
– Edward Lear

I loved wrens. Until I didn’t.

Not long after Steve and I had moved from our apartment in Chicago to our first single-family home in West Dundee, we acquired a second home—a wren house. We hoped to attract a nesting pair of house wrens, the most common wren and the species found in our area. Its name derives from its tendency to nest near human dwellings. As songbirds that prefer to nest in cavities, house wrens are especially attracted to nest boxes and seem to prefer them to natural cavities. To protect the wren house from the weather and give us a front-row seat, we hung it up in early spring under the eave at one end of our front porch and waited for the fun to begin.

Our wait wasn’t long. First, we heard a male wren singing, seemingly continuously, in the vicinity of our yard. Next, we observed him perched on the peak of the bird house roof and trilling there, estabishing his territory and claiming ownership of the nest box. Pretty soon our front steps, directly under the house, were strewn with small twigs and grasses. I grumbled about having to sweep away the daily mess, but I was also glad the male wren was setting up housekeeping in the nest box. Watching him try to fit numerous long twigs through the round opening was also a source of amusement. He would make several attempts by adjusting the twig’s angle before giving up or shortening the twig. Male wrens typically build rudimentary nests in multiple places for a female to consider as part of the courting process. Along with ours, a wren house in our next-door neighbor’s front yard was also being considered for occupancy. We hoped his chosen mate agreed with us that our wren house was a lot cuter than our neighbor’s. She would have the final say.

Through the “dummy” nest-building process, the male wren sings frequently from dawn to dusk to attract a female. Soon, we were spotting two wrens together in our front yard, acting for all the world like a partnered couple: enaging in friendly chases, foraging and feeding in close proximity, occasionally singing, sometimes squabbling, and then selecting their dwelling. I knew the female had chosen our bird house when one day I noticed the front steps were littered with even more twigs and debris than before. As is true for all breeding female wrens, once she selects a nest site, she brusquely tosses out most of the nest the male constructed and starts all over again, building it to her specifications and lining it with soft materials like grass, feathers and cocoons. It makes perfect sense. Since she alone is responsible for egg incubation, only her comfort and construction standards matter. Fun fact: Wrens sometimes place spider egg sacs into the nest; when the spiders hatch, they eat potentially harmful nest parasites.

The nest completed, we saw little of the female as she incubated the eggs, anywhere from three to ten in number, for around two weeks. One day we were excited and charmed to hear faint peeping sounds emitted by the hatchlings. We were also impressed by how diligently the male and female tended to them. Songbirds have a tough job. Unlike many waterfowl babies that can feed themselves and can walk and swim shortly after hatching, songbirds’ nestlings are essentially helpless until they fledge (i.e., leave the nest). The parents are therefore busily occupied with constant feeding during the 15 to 17 days the babies are in the nest. In that short span they are transformed from tiny, immobile, almost naked creatures to roly-poly, full-feathered birds capable of flight. By observing the adult wrens going in and out of the house to feed their young, we gained some appreciation for the wide variety of insects they consume. Caterpillars, spiders, beetles, leafhoppers, grasshoppers, flies, and various bugs are all on the menu. As they neared fledging, occasionally we could see a tiny beak and small head poking out of the hole.

We were not fortunate enough to witness the babies fledging, but I found an adorable video of baby house wrens fledging from a nest box. Watching this video, I chuckled over the babies chattering, quarreling, getting in each other’s way and pushing each other around like human siblings do. Some of them also exhibit the hesitancy common to many humans when they’re about to try a new and dangerous physical skill: getting ready to make the leap, but then thinking better of it and retreating. Once they leave the nest, the babies hang around their parents to learn how to find food and watch for predators. We hoped to see the juveniles hopping and fluttering about with the adults, but we never did. Our wren house excitement had come to an end.

There’s a lot to love about these little songbirds, and, given their huge range, healthy population and comfort around people, they have many human admirers. Wrens have the broadest reach of any songbird in the Western Hemisphere, with different species breeding from Canada down to the tip of South America. House wrens are not very picky when it comes to their habitat. If an area has trees, shrubs, tangled vegetation mixed with open areas, and loads of insects, they’re happy. Parks and yards often meet their requirements. One of their charms is their habit of choosing unusual nesting locations in manmade objects, a behavior not unknown among other species. A wide variety of birds have nested on objects ranging from the top of a stoplight, the back of a floating goose decoy, the top of the head of a large statue of a human figure, and, in the case of one hummingbird pair, the top of a patio windchime. Yet wrens so frequently engage in this behavior that one case was documented by John James Audubon in his house wren image.

There is also no question wrens are adorable to look at and observe, with several pleasing attributes that more than compensate for their unassuming plumage. Their big, feisty personality belies their tiny frames; adults’ weight matches that of two quarters. House wrens are fierce defenders of their nests. When the wren house was occupied and we’d go out the front door, we were often subjected to a chattering scolding from the male wren, as if to say, “What do you think you’re doing here?” Their round little bodies are punctuated by their tails, which they often hold in a vertical position, giving them a jaunty air. The longish, downward sloping beaks give them a slightly dour appearance that contrasts with their joyful songs. A wren singing is truly a miracle of nature. That such small birds can produce these strong, loud, complicated series of sounds, rapidly repeated at short intervals, is amazing. The wren’s song has been described variously as a “stuttering, gurgling outburst”; “a heady mixture of trills, chirps, whistles and buzzes”; “effervescent”; “rush and jumble;” and “bubbly and energetic.” Listen and decide for yourself. Hearing that cheerful sound at dawn each morning last spring and summer certainly helped me survive the pandemic year.

With so much to love about wrens, and having had an engaging experience as neighbors of a nesting pair, why did I later hesitate to put the wren house back out in the spring? My reluctance stemmed from having learned some aspects of these birds’ behavior that diminished them in my eyes. First, they are “cheaters,” as one observer put it, trading one partner for another in the middle of the breeding season, even when one brood in still in the nest. Here’s one description from A Natural History of North American Birds from Eastern and Central North America:

“…one male mated with a certain female, and while she was sitting on her eggs he left her and mated with another female, joining her in nesting in another box. The first female hatched her brood, fed them for a while, and then apparently became enamored of another male, brought her first male back to attend to her brood, and went away with her new lover ansd started another family while the first male fed and reared her first brood. Such actions would constitute a scandal in polite society.”

Second, and much more disconcerting, I found out wrens have a nasty habit of puncturing the eggs or killing the hatchlings of other species that made the unfortunate decision to nest in the wren’s territory. I was especially alarmed when I learned that chickadees and bluebirds, favorite species of mine, count among their victims. Having made those discoveries, I seriously considered leaving our wren house in the garage, collecting dust and unoccupied, that next spring.

Eventually I reached a different conclusion. I reflected on how we tend to judge all creatures, for good or ill, according to our uniquely human viewpoint. The same human perspective that prompts us to like wrens in part because they tolerate us and often raise young close by also engenders disapproval of wrens’ unfaithfulness and slaughter of innocent baby birds. I realized I could admire the bald eagle’s awe-inspiring soaring ability even though it often steals other raptors’ captured prey. I can appreciate the many different bird species that make nestlings a regular part of their diet, knowing it’s part of the natural order of things. And I could understand the wrens are following their instincts to maximize the health and survival chances of their progeny and relish hearing their exuberant songs without reservation. I put the wren house back up.

On a spring day last year I was jogging along the Fox River bike trail when I heard a red-winged blackbird’s warning call, which is a piercing single-note whistle. He was perched on a low branch of a tree along the trail up ahead and, as I approached, his calls became more frequent and insistent. Living near a river, I see and hear many of these these birds regularly, so I didn’t think anything of it. This time I was in for a surprise. When I reached the tree, he took off but then swooped down and flew right in front of my face before coming back and making contact with the top of my head. Fortunately, I was uninjured, but I picked up my pace to leave the area quickly. While the incident didn’t spark the kind of terror the denizens of Bodega Bay experienced in Hitchcock’s 1963 film The Birds, it was disconcerting nonetheless. Ever since that day, I’ve worn a hat when I go jogging in the spring and summer.

I didn’t blame the blackbird. He was simply doing his all-important job of protecting his nest. Red-winged blackbirds often build their nest close to the ground in marsh vegetation, shrubs, or trees near water, so I could easily have been too close for comfort as I passed by. These birds, which are widespread and not shy about nesting near where humans live, including in urban areas, have become well known for aggressive nest defenses. Every year, local news outlets all over North America report blackbirds harrassing humans; usually the victims are unsuspecting people just passing by, as I was. In 2020, a Toronto resident video recorded one bird as it dive-bombed multiple pedestrians. The bird now has a TikTok account and social media handle: Dive Bomber Dave. Red-winged blackbirds also dive-bomb much larger bird species that stray too near their nest, such as great blue herons and large raptors.

The red-winged blackbirds’ tenacious nest defense makes sense: the eggs and the hatched nestlings are extremely vulnerable to predators. The list of predators is long. Among them: dogs, coyotes, foxes, snakes, raccoons, squirrels, rats, weasels, and numerous bird species. Probably the main culprit is domestic cats, including house cats, strays, and feral cats, which kill billions of birds worldwide each year. Waterfowl hatchlings have additional worries, including snapping turtles and some species of fish. With so many threats to their young, bird species exhibit a variety of behaviors to protect their nests from danger. In addition to the single-bird aerial assault of the red-winged blackbirds, I have observed several other categories of nest-defense behavior in birds: mobbing, gound assaults, and, my personal favorite, deception.

Mobbing follows the principle that there is strength in numbers. It’s basically an aerial assault by more than one bird on a potential threat, most commonly a predator bird such as a hawk or owl. The objective? To bother the encroaching creature enough that it decides to leave the area. Two days ago I was sitting in my car waiting for a red light to turn green when I saw a red-tailed hawk in flight being mobbed by a group of five much smaller birds (too small for me to identify). The attackers took turns swooping down in front of the hawk’s face and occasionally making contact with the hawk’s back or head. This cooperative defensive behavior is a common sight during the nesting season. Birds as small as chickadees, sparrows, and swallows and as large as ravens and crows engage in mobbing behavior; some observers have seen dozens of birds mobbing a single raptor.

You might be wondering, what chance would the smaller birds have against a large predator? In flight, the smaller birds have a huge advantage of maneuverability—like a Boeing 747 vs. a fighter jet. And a group of birds harassing and attacking the hawk is a much more effective deterrent than one solo assailant. Even if the hawk were able to pick off one of the harassers, the remaining birds would continue the assault. Since it’s to the advantage of many birds to drive a raptor away from a breeding territory, the mobbing group will sometimes include birds from more than one species. A number of different species emit a similar-sounding warning call that alerts them to the presence of a predator. These warning calls both eliminate the predator bird’s advantage of surprise and can serve to recruit potential fellow mobbers. On more than one occasion I have seen the mobbers’ objective met: the irritated intruder flew off, and the triumphant mobbing birds returned to their nesting area.

In another tactic, some birds, especially ground nesters, try to intimidate an intruder with a fierce display. When I observed a group of goslings at close range recently, under the watchful eye of the gander (as I reported in my last post), I knew enough about goose ground assaults to step away as soon as the gander opened his beak to display his serrated bill. He was giving me a clear warning. On numerous occasions I have seen a goose defend its nest, and it’s an impressive and imposing spectacle. If the goose’s loud, vehement, continuous honking doesn’t do the trick, it raises its wings to expand in size and charges straight at the intruder with neck fully stretched out front while raising a verbal ruckus. They also sometimes fly at the intruder to bite and strike with its feet. You truly don’t want to mess with their nests or their goslings.

My favorite bird protective behaviors involve deception, some of which are aural in nature. The burrowing owl, a small, yellow-eyed desert and grassland inhabitant that nests in underground burrows, can accurately mimic the unmistakable warning rattling sound of a rattlesnake, which is intended to ward off some of the owl’s predators. In a visual deception, plovers and some other ground-nesting birds will try to lure a predator away from its nest by scurrying head down and low to the ground to impersonate a rodent.

I first witnessed bird trickery many years ago, when a killdeer fooled me with its acting prowess. I became aware of its presence when I heard its shrill, high-pitched alarm calls, which became increasingly intense and rapid-fire. I spotted the bird as it landed on the ground not far away from me. After landing, it flopped around, its wings at odd and painful-looking angles, all the while calling out as if in distress. Concerned, I slowly approached to see if it was injured. It continued its performance, moving away as I approached, until it decided I was far enough from the nest and calmly flew off. Its wings were sound and intact, but my pride was sorely wounded. The objective of the killdeer’s broken-wing act is to distract a predator away from the nest area or its babies and lure it toward the seemingly disabled adult. Clearly, I can attest its effectiveness.

Robin-sized birds who lay their eggs on a bare patch of ground out in the open, killdeer were named after the sound of their main vocalization, like chickadees were. Killdeer pull out all the stops when it comes to protecting their eggs and young. Speckled in a fine dark gray and white pattern, their smalls eggs are well camouflaged. If an intruder comes too close to the nest, the killdeer issues its warning call and, depending on the threat, will act its broken-wing distraction, take an aggressive posture with outstretched wings, or even charge at the potential predator. Here are first-hand accounts of two of those tactics from Life Histories of North American Birds, by Arthur Cleveland Bent, showing they don’t lack courage:

“Howard Lacey (1911) noticed that a flock of driven goats divided. ‘I walked up to the place expecting to find a rattlesnake, and found instead a killdeer standing over her eggs with upspread wings and scolding vigorously.’ Norman Criddle (1908) writes, ‘If the danger came from a cow or horse, the tactics were changed and the birds with both wings and feathers spread out would run into the animal’s face, and so by startling it drive the intruder away.’”

As I have learned, there’s high drama among birds during the nesting season, with avian actors contributing their fair share of the spectacle.

“Preparation” by Paul Laurence Dunbar

The little bird sits in the nest and sings
A shy, soft song to the morning light;
And it flutters a little and prunes its wings.
The song is halting and poor and brief,
And the fluttering wings scarce stir a leaf;
But the note is a prelude to sweeter things,
And the busy bill and the flutter slight
Are proving the wings for a bolder flight!

I was engaged in a staring contest with a Canada goose. I lost.

In a recent stroll along the Fox River, I came upon a family of Canada geese. There were mom and dad in the charming company of their six adorable, fluffy offspring, busily grazing on fresh spring grass along the narrow strip of greenway between the sidewalk and the bank sloping down to the water. I should clarify: the male goose was not doing any eating. Mating pairs of Canada geese follow traditional gender roles: the female builds the nest and incubates the eggs, while the male, the gander, serves as guard and protector. As I approached, this gander was faithfully and diligently doing his job. The closer I got to his family, the more erect his posture became, and he locked his black eyes on mine. When I got to a spot opposite where mama and goslings were gorging on sweet shoots of grass, he was on high alert and positioned himself between me and his family. I was no more than eight feet from him.

Out of curiosity (or foolhardiness, if you prefer), I decided to stand there for a short while to observe the gander’s behavior. I stayed completely still, as did he. Over the next five minutes, he never budged or took his eyes off of mine. I was impressed that his family didn’t pay any attention to me, so trusting were they of his ability to protect them. When I became restless, I decided to try a little experiment: what would I need to do to prompt a reaction from him? I started by simply leaning my upper body slightly in his direction. That was enough. He opened his mouth wide, calling attention to his bill and tongue, both of which are serrated. Ouch. It was the goose equivalent of a suspicious dog baring its teeth. I wisely decided to walk on. Score one for the geese. Impressed by this bird’s pluck, I smiled as I went on my way.

Around here, it’s as if the Canada geese are in charge. Countless times since we moved here nine years ago, I’ve had to stop and wait in my car on a local street while some geese strolled across the thoroughfare. And I mean stroll. Blissfully unconcerned about the traffic jam they’re causing, the geese are seldom in any particular hurry in that situation. If you’re in the lead car, the lead goose invariably gives you a defiant look as if to say, “Don’t even THINK about moving. We OWN this place.” I find their bossiness and fearlessness endearing, but not everyone feels the same way about these large birds.

Canada geese have a PR problem. They seem to be everywhere: golf courses, public parks and parking lots, yards abutting or near water, retention ponds on corporate campuses, plowed corn fields. Wherever they are, they tend to take over. As herbivores with a diet consisting mostly of grasses, they are prolific poopers, creating unsightly messes on walkways and expanses of manicured lawns. Geese are quite vocal and loud. Some people find their honking less than poetic when the geese are their neighbors. Occasionally they also contribute to dramatic news headlines. There have been numerous reports of Canada geese attacking passers-by. There was also the well-known incident in 2009, when US Airways flight 1549 encountered a flock of migratory Canada geese after taking off from La Guardia Airport in New York. The birds are large enough that the collision resulted in a total loss of engine power. While the pilot landed the aircraft safely on the Hudson River, no human lives were lost, and Tom Hanks starred in the 2016 film inspired by the incident, the Canada geese struck by the aircraft didn’t fare so well, and the species’ reputation suffered another blow.

While it will surprise no one that conservationists classify this species as “least concern” from a population perspective, Canada geese weren’t always so numerous. By the early twentieth century, overhunting and habitat loss had dropped their numbers considerably. By the end of the century, conservation efforts and the reduction of their natural predators led to their rebound. And their numbers continue to increase, in some cases dramatically. Credit the adapatability of the Canada goose for its continued rise. It has learned to be comfortable around humans and has decided that some of our manmade landscapes are ideal habitats. Take parks and gold courses, for example. There is often water close by, which is a requirement, and they typically have large areas featuring the birds’ main source of food: grass. Even better, the well-tended lawns give them a sense of security; their openness makes it harder for a predator to sneak up on the geese. The birds have found some of these places in urban and semiurban areas so pleasing that increasing numbers of the north-breeding populations no longer migrate south for the winter. We have our own group of permanent residents here. Often in winter months I have seen them in local parks rooting around with their bills to find grass under the snow.

As much as I am not fond of dodging goose poop on the sidewalks of my favorite park, I have to admire their gumption, flexibility, and ability to survive – and even thrive – as their environment has changed. There is much else to admire about these large waterfowl. Those that migrate fly in their recognizable V formation, with experienced geese taking turns as the leader of the flock. This V formation, which is also used by aircraft flying together, reduces the birds’ wind resistance, enabling them to use their energy more efficiently. Canada geese can fly up to 1,500 miles in one day in favorable weather conditions.

My park encounter with the gander was evidence of how protective the geese are as parents. They can be downright fierce keeping any potential predators away from the nest and goslings – including other geese that invade their nest territory – and most of their aggression toward humans is to defend their young. Once the goslings hatch, they are fully able to walk, swim, and eat; the parents are on guard duty until the goslings reach maturity. Some of the adults also display a fascinating co-parenting behavior after the goslings hatch. After witnessing a pair of geese loudly and forcefully defend their nest from an encroaching goose pair a few weeks ago, I was surprised last week to see ten goslings peacefully swimming along with four adults. I have since learned that when there are a lot of geese nesting in relatively close proximity, different sets of parents will sometimes bring their goslings together, with the adults sharing babysitting duties. These groups are called crèches. Sometimes a large group of goslings (as many as 30 or more have been seen) will be overseen periodically by just one or two adults, which gives the other parents a welcome respite from their protector role. It’s another ingenious goose adaptation.

In a world where our natural environment is under relentless change, it is reassuring to me that the unmistakable sound of honking geese flying overhead will continue to be heard for some time to come. What’s good for the goose is our understanding.