Nature, Syncopated
Laura England | November 2019
This crisp fall afternoon I sit working at the dining room table that once belonged to my great grandmother, then my grandmother, my mother and now me. For generations around this “Good Oak” we have enacted and evolved the lifeway of our family—exploring, strengthening and, at times, testing our bonds. A flash in my periphery halts me. Who is it now? I consult the Peterson guide we leave on top of the corner cabinet for this purpose. It’s a Winter Wren, come to fuel up at our feeder on its way south. My son, Gabe, in his 10-year-old script, adds the species name to the backyard bird list we started six months ago, joining Black-capped Chickadee, Tufted Titmouse, White-breasted Nuthatch, Dark-eyed Junco, Song Sparrow, and many more. I hurry my attention back to my laptop in front of me.
Hurry. Modern life is by the clock, and increasingly divorced from the changing seasons of the natural world. Capitalism dictates that we maximize productivity year-round, regardless of what’s happening outside our climate-controlled abodes. We do all we can to prevent weather from disrupting our plans, and when it does we are thoroughly vexed. Meanwhile, outside every living thing responds to weather conditions, with involuntary physiological and/or behavioral adjustments. Responsiveness to weather is ancient heritage, stemming from hundreds of millions of years of evolution, and promotes health, survival and reproductive success. Yet our kind stubbornly forges ahead with daily plans, however unimportant they may be, ignoring the changing seasons.
Beyond our species, the timing of the seasons quite literally governs lives. The timing of essential life activities and events—what ecologists call “phenology”—is driven by seasonal cues from the environment. Over millions of years, relationships between diverse lifeforms evolved to play out in concert across the seasons. For example, insect pollinators emerge in the spring just when the plants whose nectar they need to drink (and whose pollen they’ll unwittingly disperse) are blooming their hearts out. These phenological synchronies are essential to the survival of individuals, the persistence of populations, and the functioning of ecosystems all around us.
But as our climate changes, the timing of the seasons changes too, creating an urgent challenge for living things to keep up. Some species are keeping time with climate disruptions while others lag various degrees behind, leading to strained and even severed relationships between species. Nature’s symphony is increasingly syncopated. Syncopation—the displacement of rhythmic accents associated with regular metrical patterns—disrupts listeners’ expectations and creates a feeling of “forward drive.” Climate change is the forward drive of our time, the force disrupting timing, patterns and expectations for all living things.
Migratory birds, for whom timing is everything, provide a troubling example of “nature, syncopated.” Many birds time their spring migration to match the phenology of their insect prey, in particular relying on emerging insects in their breeding grounds at the end of their hundreds to thousands of miles of flight. Voracious consumption of insects helps them to compensate for energy lost during migration, but more importantly to meet the energetic demands of another journey—their journey through parenthood. Dense packets of energy in hexapod form fuel these birds in establishing their territories, nesting, breeding, laying eggs, and hatching and rearing their chicks. The concurrent timing of breeding bird arrival with insect emergence in their spring breeding grounds matches peak insect demand with peak supply, and has made generation after generation of these migratory birds possible. But now climate change is damaging this longstanding linkage.
Recently, avian ecologists undertook the first continental scale study of climate change induced phenological asynchrony (Mayor et al. 2017), which demonstrated that some birds are falling further and further off the beat. Focusing on 48 passerine (i.e. perching) bird species in North America from 2001 to 2012, these scientists used observations from The Cornell Lab of Ornithology’s eBird—the world’s largest biodiversity-related citizen science project—to estimate the timing of birds’ arrival in their breeding grounds each year. They used satellite imagery to determine the timing of spring green-up, which is strongly correlated with the emergence of leaf-eating insects, and serves as a proxy for the timing of peak food availability for these birds in their breeding grounds.
Their findings? Spring green-up is coming earlier each year. And though most of the bird species in this study adjusted their breeding ground arrival dates to some extent, nine species lagged behind the pace of change in spring green-up. Of the eastern forest birds studied, the Yellow-billed Cuckoo (Coccyzus americana) is lagging the most, with phenological asynchrony growing by more than one day per year. Late penalties are severe—not only are their insect prey consumed by the more climate-adaptable migrants, but the leaves that support herbivorous insects produce more defensive compounds as the growing season progresses, which means insect prey populations begin to decline soon after green-up.
So laggards like the Yellow-billed Cuckoo don’t get as much to eat, and may not be so successful completing their journey through parenthood. Some would-be cuckoo fathers may not have enough oomph to regale the females with their best songs and win over a mate. Once paired, hungry cuckoos may fail to build a nest that is sound enough to safely hold their eggs. Starved cuckoo mothers may not have enough energy, after mating, to produce as many eggs as usual. Cuckoo parents may lack the vigor needed to defend their chicks from predators. All of this adds up to fewer new cuckoos each year. According to the North American Breeding Bird Survey, Yellow-billed Cuckoo populations declined by about 52% between 1966 and 2015. The species conservation status is listed as “Common Bird in Steep Decline” (2014 State of the Birds Report).
Nearly half a million citizen observations of the Yellow-billed Cuckoo have been reported on eBird over the years. We are certainly witnessing this bird, but are we truly seeing its struggle? It’s rather ironic that this particular species is such a straggler since cuckoos are the birds we most associate with keeping time. The call of the cuckoo has been marking the hours since the first cuckoo clocks were made in the early 17th century in the German state of Saxony. Perhaps Germany’s cuckoo species are keeping time and adapting to climate disruption better than ours.
We may someday feel the consequences of our cuckoos’ climate-induced syncopation in serious ways. Caterpillars are the feast of choice for Yellow-billed Cuckoos; individual birds eat thousands of caterpillars each year, helping to control outbreaks of tent caterpillars that can decimate eastern forests. Late cuckoos may mean more tent caterpillars devouring more leaves and turning forest canopies to filigree. And damage to our forests means more carbon dioxide left in the atmosphere, further warming the planet.
So what is behind this bird-insect asynchrony? Birds are cued to migrate primarily by seasonal changes in photoperiod (i.e., day length), which is determined by the tilt of the Earth on its axis as it orbits the sun. So bird migration cues are consistent from year to year. In contrast, conditions at birds’ breeding grounds—namely, the timing of spring green-up and concurrent emergence of insect prey—is cued primarily by temperatures and is therefore altered by rapid global warming.
Frankly, I find it amazing that most of the bird species studied did not exhibit increasing asynchrony, or at least not enough to be statistically significant. Perhaps the study period of just a dozen years was too short to detect it. Or, more optimistically, these birds demonstrated what evolutionary biologists call “phenotypic plasticity,” the capacity to adapt to changing environmental conditions. I wonder though, how in the world can flocks of birds in their wintering grounds anticipate changing food availability hundreds or thousands of miles away in their breeding grounds and then accordingly adjust their migration start date, flight speed, and/or the length of stops along the way?
The answer lies in their evolutionary heritage and the necessity of adaptability. But the study authors noted, “although birds have had to adapt to climatic shifts and resulting asynchronies with resources throughout their evolutionary history, the current rate and magnitude of change have exceeded normal bounds” (Mayor et al. 2017). As bird evolution progresses into the Anthropocene, accelerating global warming and associated disruptions will serve as increasingly powerful selection pressures, choosing winners and losers among not just the avian community, but among all living things. The Yellow-billed Cuckoo appears likely to be among the losers.
In the avian world, there are lots of losers. A landmark study published this October concluded that compared to 1970, North America now has nearly 3 billion fewer birds (Rosenberg et al. 2019). Three billion; we’ve lost more than a quarter of our birds. Actually, I challenge the use of the language of ecological loss—"wetland loss,” “biodiversity loss,” “bird loss.” We cowardly use this passive language that ignores our active, destructive role. We have destroyed birds’ possibilities in various and sundry ways, not just through climate change, but by destroying their habitats, contaminating soil and water with pesticides and other toxic substances, and by unleashing millions of cat predators.
Also in October of this year, a study of more than 70,000 specimens of birds across 52 species found a significant, consistent association between warming temperatures and declining bird body size over the past 40 years. The authors of the study suggest various possible explanations, including climate change-driven phenological mismatches between birds and their food sources (Weeks et al. 2019). North American migratory birds are both shrinking and disappearing.
These thoughts haunt me as I witness the birds at my feeder. Chickadees peck away at seeds embedded in suet, blissfully unaware of the broader disturbances wreaked by our own appetite for energy, by our unearthing and combustion of ancient sunlight. Yet the pressures for my little chickadee, and all living things, to adapt accelerates.
In his book, Flight Ways: Life and Loss at the Edge of Extinction, Thom Van Dooren emphasizes the dynamic nature of species; they’re always in the “process of becoming—of adaptation and transformation” (2014, p. 28). He aptly describes an individual bird as “a single knot in an emergent lineage: a vital point of connection between generations—generations that do not just happen, but must be achieved” (Van Dooren 2014, p. 27). The ancestors of modern birds emerged nearly 100 million years ago and have been adapting and transforming since. I wonder what, if any remain, avian descendants will look like in 100 million more.
Whether we’re willing to admit it or not, climate change threatens our own lifeways as much as the flight ways of the birds. When I look at my own children, my family’s “embodied intergenerational achievement” (Van Dooren 2014, p 27), I worry about what they’ll have to adapt to decades from now as they face the climate disruptions that are already locked into their futures.
A neologism captures the essence of this particular feeling—shadowtime. “Shadowtime manifests as a feeling of living in two distinctly different temporal scales simultaneously, or acute consciousness of the possibility that the near future will be drastically different than the present” (Bureau of Linguistic Reality 2015). How will my own children fare in a world with syncopated nature and all that comes with it, including fewer birds?
For now, we’ll keep gathering around this good oak, cultivating our “rich, but imperfect relationships of inheritance, nourishment, and care” (Van Dooren 2014, p 27), and witnessing the birds whose flight ways intersect with our own.
SOURCES
Bureau of Linguistic Reality. https://bureauoflinguisticalreality.com/portfolio/shadowtime/
Cornell Lab of Ornithology. All About Birds https://www.allaboutbirds.org/guide/Yellow-billed_Cuckoo/
Mayor, S.J. et al. 2017. Increasing phenological asynchrony between spring green-up and arrival of migratory birds. Scientific Reports 7: 1902, doi:10.1038/s41598-017-02045-z
Rosenberg, K. V. et al. 2019 Decline of the North American avifauna. Science 366: 120–124.
Van Dooren. T. 2014. Flight Ways: Life and Loss at the Edge of Extinction. New York: Columbia University Press.
Weeks, et al. 2019. Shared morphological consequences of global warming in North American migratory birds. Ecology Letters doi: 10.1111/ele.13434.
Laura England | November 2019
This crisp fall afternoon I sit working at the dining room table that once belonged to my great grandmother, then my grandmother, my mother and now me. For generations around this “Good Oak” we have enacted and evolved the lifeway of our family—exploring, strengthening and, at times, testing our bonds. A flash in my periphery halts me. Who is it now? I consult the Peterson guide we leave on top of the corner cabinet for this purpose. It’s a Winter Wren, come to fuel up at our feeder on its way south. My son, Gabe, in his 10-year-old script, adds the species name to the backyard bird list we started six months ago, joining Black-capped Chickadee, Tufted Titmouse, White-breasted Nuthatch, Dark-eyed Junco, Song Sparrow, and many more. I hurry my attention back to my laptop in front of me.
Hurry. Modern life is by the clock, and increasingly divorced from the changing seasons of the natural world. Capitalism dictates that we maximize productivity year-round, regardless of what’s happening outside our climate-controlled abodes. We do all we can to prevent weather from disrupting our plans, and when it does we are thoroughly vexed. Meanwhile, outside every living thing responds to weather conditions, with involuntary physiological and/or behavioral adjustments. Responsiveness to weather is ancient heritage, stemming from hundreds of millions of years of evolution, and promotes health, survival and reproductive success. Yet our kind stubbornly forges ahead with daily plans, however unimportant they may be, ignoring the changing seasons.
Beyond our species, the timing of the seasons quite literally governs lives. The timing of essential life activities and events—what ecologists call “phenology”—is driven by seasonal cues from the environment. Over millions of years, relationships between diverse lifeforms evolved to play out in concert across the seasons. For example, insect pollinators emerge in the spring just when the plants whose nectar they need to drink (and whose pollen they’ll unwittingly disperse) are blooming their hearts out. These phenological synchronies are essential to the survival of individuals, the persistence of populations, and the functioning of ecosystems all around us.
But as our climate changes, the timing of the seasons changes too, creating an urgent challenge for living things to keep up. Some species are keeping time with climate disruptions while others lag various degrees behind, leading to strained and even severed relationships between species. Nature’s symphony is increasingly syncopated. Syncopation—the displacement of rhythmic accents associated with regular metrical patterns—disrupts listeners’ expectations and creates a feeling of “forward drive.” Climate change is the forward drive of our time, the force disrupting timing, patterns and expectations for all living things.
Migratory birds, for whom timing is everything, provide a troubling example of “nature, syncopated.” Many birds time their spring migration to match the phenology of their insect prey, in particular relying on emerging insects in their breeding grounds at the end of their hundreds to thousands of miles of flight. Voracious consumption of insects helps them to compensate for energy lost during migration, but more importantly to meet the energetic demands of another journey—their journey through parenthood. Dense packets of energy in hexapod form fuel these birds in establishing their territories, nesting, breeding, laying eggs, and hatching and rearing their chicks. The concurrent timing of breeding bird arrival with insect emergence in their spring breeding grounds matches peak insect demand with peak supply, and has made generation after generation of these migratory birds possible. But now climate change is damaging this longstanding linkage.
Recently, avian ecologists undertook the first continental scale study of climate change induced phenological asynchrony (Mayor et al. 2017), which demonstrated that some birds are falling further and further off the beat. Focusing on 48 passerine (i.e. perching) bird species in North America from 2001 to 2012, these scientists used observations from The Cornell Lab of Ornithology’s eBird—the world’s largest biodiversity-related citizen science project—to estimate the timing of birds’ arrival in their breeding grounds each year. They used satellite imagery to determine the timing of spring green-up, which is strongly correlated with the emergence of leaf-eating insects, and serves as a proxy for the timing of peak food availability for these birds in their breeding grounds.
Their findings? Spring green-up is coming earlier each year. And though most of the bird species in this study adjusted their breeding ground arrival dates to some extent, nine species lagged behind the pace of change in spring green-up. Of the eastern forest birds studied, the Yellow-billed Cuckoo (Coccyzus americana) is lagging the most, with phenological asynchrony growing by more than one day per year. Late penalties are severe—not only are their insect prey consumed by the more climate-adaptable migrants, but the leaves that support herbivorous insects produce more defensive compounds as the growing season progresses, which means insect prey populations begin to decline soon after green-up.
So laggards like the Yellow-billed Cuckoo don’t get as much to eat, and may not be so successful completing their journey through parenthood. Some would-be cuckoo fathers may not have enough oomph to regale the females with their best songs and win over a mate. Once paired, hungry cuckoos may fail to build a nest that is sound enough to safely hold their eggs. Starved cuckoo mothers may not have enough energy, after mating, to produce as many eggs as usual. Cuckoo parents may lack the vigor needed to defend their chicks from predators. All of this adds up to fewer new cuckoos each year. According to the North American Breeding Bird Survey, Yellow-billed Cuckoo populations declined by about 52% between 1966 and 2015. The species conservation status is listed as “Common Bird in Steep Decline” (2014 State of the Birds Report).
Nearly half a million citizen observations of the Yellow-billed Cuckoo have been reported on eBird over the years. We are certainly witnessing this bird, but are we truly seeing its struggle? It’s rather ironic that this particular species is such a straggler since cuckoos are the birds we most associate with keeping time. The call of the cuckoo has been marking the hours since the first cuckoo clocks were made in the early 17th century in the German state of Saxony. Perhaps Germany’s cuckoo species are keeping time and adapting to climate disruption better than ours.
We may someday feel the consequences of our cuckoos’ climate-induced syncopation in serious ways. Caterpillars are the feast of choice for Yellow-billed Cuckoos; individual birds eat thousands of caterpillars each year, helping to control outbreaks of tent caterpillars that can decimate eastern forests. Late cuckoos may mean more tent caterpillars devouring more leaves and turning forest canopies to filigree. And damage to our forests means more carbon dioxide left in the atmosphere, further warming the planet.
So what is behind this bird-insect asynchrony? Birds are cued to migrate primarily by seasonal changes in photoperiod (i.e., day length), which is determined by the tilt of the Earth on its axis as it orbits the sun. So bird migration cues are consistent from year to year. In contrast, conditions at birds’ breeding grounds—namely, the timing of spring green-up and concurrent emergence of insect prey—is cued primarily by temperatures and is therefore altered by rapid global warming.
Frankly, I find it amazing that most of the bird species studied did not exhibit increasing asynchrony, or at least not enough to be statistically significant. Perhaps the study period of just a dozen years was too short to detect it. Or, more optimistically, these birds demonstrated what evolutionary biologists call “phenotypic plasticity,” the capacity to adapt to changing environmental conditions. I wonder though, how in the world can flocks of birds in their wintering grounds anticipate changing food availability hundreds or thousands of miles away in their breeding grounds and then accordingly adjust their migration start date, flight speed, and/or the length of stops along the way?
The answer lies in their evolutionary heritage and the necessity of adaptability. But the study authors noted, “although birds have had to adapt to climatic shifts and resulting asynchronies with resources throughout their evolutionary history, the current rate and magnitude of change have exceeded normal bounds” (Mayor et al. 2017). As bird evolution progresses into the Anthropocene, accelerating global warming and associated disruptions will serve as increasingly powerful selection pressures, choosing winners and losers among not just the avian community, but among all living things. The Yellow-billed Cuckoo appears likely to be among the losers.
In the avian world, there are lots of losers. A landmark study published this October concluded that compared to 1970, North America now has nearly 3 billion fewer birds (Rosenberg et al. 2019). Three billion; we’ve lost more than a quarter of our birds. Actually, I challenge the use of the language of ecological loss—"wetland loss,” “biodiversity loss,” “bird loss.” We cowardly use this passive language that ignores our active, destructive role. We have destroyed birds’ possibilities in various and sundry ways, not just through climate change, but by destroying their habitats, contaminating soil and water with pesticides and other toxic substances, and by unleashing millions of cat predators.
Also in October of this year, a study of more than 70,000 specimens of birds across 52 species found a significant, consistent association between warming temperatures and declining bird body size over the past 40 years. The authors of the study suggest various possible explanations, including climate change-driven phenological mismatches between birds and their food sources (Weeks et al. 2019). North American migratory birds are both shrinking and disappearing.
These thoughts haunt me as I witness the birds at my feeder. Chickadees peck away at seeds embedded in suet, blissfully unaware of the broader disturbances wreaked by our own appetite for energy, by our unearthing and combustion of ancient sunlight. Yet the pressures for my little chickadee, and all living things, to adapt accelerates.
In his book, Flight Ways: Life and Loss at the Edge of Extinction, Thom Van Dooren emphasizes the dynamic nature of species; they’re always in the “process of becoming—of adaptation and transformation” (2014, p. 28). He aptly describes an individual bird as “a single knot in an emergent lineage: a vital point of connection between generations—generations that do not just happen, but must be achieved” (Van Dooren 2014, p. 27). The ancestors of modern birds emerged nearly 100 million years ago and have been adapting and transforming since. I wonder what, if any remain, avian descendants will look like in 100 million more.
Whether we’re willing to admit it or not, climate change threatens our own lifeways as much as the flight ways of the birds. When I look at my own children, my family’s “embodied intergenerational achievement” (Van Dooren 2014, p 27), I worry about what they’ll have to adapt to decades from now as they face the climate disruptions that are already locked into their futures.
A neologism captures the essence of this particular feeling—shadowtime. “Shadowtime manifests as a feeling of living in two distinctly different temporal scales simultaneously, or acute consciousness of the possibility that the near future will be drastically different than the present” (Bureau of Linguistic Reality 2015). How will my own children fare in a world with syncopated nature and all that comes with it, including fewer birds?
For now, we’ll keep gathering around this good oak, cultivating our “rich, but imperfect relationships of inheritance, nourishment, and care” (Van Dooren 2014, p 27), and witnessing the birds whose flight ways intersect with our own.
SOURCES
Bureau of Linguistic Reality. https://bureauoflinguisticalreality.com/portfolio/shadowtime/
Cornell Lab of Ornithology. All About Birds https://www.allaboutbirds.org/guide/Yellow-billed_Cuckoo/
Mayor, S.J. et al. 2017. Increasing phenological asynchrony between spring green-up and arrival of migratory birds. Scientific Reports 7: 1902, doi:10.1038/s41598-017-02045-z
Rosenberg, K. V. et al. 2019 Decline of the North American avifauna. Science 366: 120–124.
Van Dooren. T. 2014. Flight Ways: Life and Loss at the Edge of Extinction. New York: Columbia University Press.
Weeks, et al. 2019. Shared morphological consequences of global warming in North American migratory birds. Ecology Letters doi: 10.1111/ele.13434.