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Want to save millions of migratory birds? Turn off your outdoor lights in spring and fall



Billions of migratory birds pass through the night sky each spring and fall. Birds use stars to orient their journey between summer breeding grounds and winter feeding grounds. The artificial lights produced by humans disrupt the migration of birds, often with fatal consequences.

The dangerous impact of artificial lights from towers and skyscrapers have long been known to scientists. Birds are drawn to the artificial lights that occupy their airspace, and their navigational compasses are short-circuited by the unusual presence of light. A well-lit high-rise building can kill hundreds of migratory birds in a single night, and it’s common to find thousands of lifeless birds at the base of skyscrapers after a busy period of migration.

What about ground-level artificial lights that shine up from our backyards and buildings? Might these artificial lights also have negative consequences for passing migrants? And how could we benefit birds if we turned out the lights?

Tracking birds through sound

In my research laboratory at the University of Windsor, we study the ecology and conservation of birds using bioacoustic tools such as sound recording and sound playback. Birds produce an extraordinary diversity of sounds that allow us to locate them and study their behaviour. By eavesdropping on bird vocalizations, we can learn about bird movements and social activities, even under cover of darkness.

Many species of nocturnal migrants produce vocalizations when they are in active flight. These short and simple calls are known as flight calls, and they are thought to play a role in communication between birds within migratory flocks. Many flight calls are species-specific and therefore we can identify which type of birds are passing overhead at night. By recording these calls, we can measure the biodiversity of migrants simply by pointing microphones at the night sky. Examples of flight calls from six species of migratory birds. Dan Mennill, Author provided389 KB (download)

Recently, we used bioacoustic recordings of flight calls to study the effects of artificial light on migratory birds. We focused on ground-level artificial lights, the kind of lights that many of us use to illuminate our porches or driveways, or to provide landscape lighting in our backyards.

Lights change bird behaviour

During fall migration, my student Matt Watson and I collected recordings of the sky at 16 pairs of sites near Lake Erie. Each pair of sites included a dark location with no artificial lights and a nearby location with a back porch light or street lamp. We recorded from sunset to sunrise and then tallied all of the flight calls in every recording. We used these data to ask the question: Does the presence of ground-level lighting change the behaviour of birds moving overhead?

Prof. Dan Mennill with a flight call microphone and a digital recorder for recording migratory birds. Dan Mennill, Author provided

We detected far more flight calls from migratory birds above sites with artificial lights than nearby dark sites. On average there were three times as many calls recorded over sites with ground-level artificial lights. Therefore, artificial light increases the number of flight calls produced by birds migrating overhead.

Furthermore, we detected more species of birds calling above sites with artificial lights. We found that the acoustic biodiversity was almost 50 per cent higher above sites with ground-level artificial lights.

We are still exploring the mechanism behind these patterns. One possibility is that more birds pass over sites with artificial lights. A second possibility is that birds fly at lower altitudes over sites with artificial lights. A third possibility is that ground-level lights disorient passing birds, leading them to call more often.

Observations of birds at the 9-11 memorial in New York City, Tribute In Light, reveals that ground-level lights can distract migratory birds. Our recordings suggest that a similar phenomenon occurs even with backyard lights. Whatever the mechanism, our results are surprising and alarming, because they teach us that even low-powered outdoor lights change the behaviour of migratory birds overhead.

Birds flying at night at the Tribute in Light at in New York City.

Lights and sounds create a deadly trap

A new study was recently published on the effects of ground-level artificial lights on nocturnal migrants. For 40 years, researchers at the Field Museum have collected dead birds from the base of well-lit buildings on Chicago’s waterfront. Over this time, they found more than 35,000 dead birds next to the windows of a single ground-level building.

Motivated in part by our bioacoustic studies of the effects of artificial light on migratory birds, the authors of the Chicago study asked an intriguing question: Are fatal window collisions related to the calling behaviour of birds?

The authors found a striking pattern. The bird species that were killed most often were the species well-known for their behaviour of producing calls during migration. The species that appeared rarely at the base of lit windows were species that are not known to produce flight calls.

For example, the most common birds collected after a fatal window collision were white-throated sparrows, dark-eyed juncos and song sparrows. All of these species produce flight calls. In contrast, warbling vireos, blue-grey gnatcatchers and eastern phoebes were rarely found dead next to lit windows, even though these animals are common nocturnal migrants in the Chicago area. None of these species produce flight calls.

This suggests that the propensity of bird species to produce flight calls is connected to the risk of birds making fatal collisions with artificially lit windows.

This new finding raises the possibility that some bird species are especially susceptible to these deadly traps. A passing migrant that is distracted by artificial light may produce a flight call. That flight call may attract other passing migrants, bringing them closer to danger. In this way, the negative impacts of ground-level lights appear to be especially severe for birds that routinely produce flight calls.

Turning out the lights

A clear and growing scientific consensus teaches us that artificial lights have a negative impact on migratory birds. Amid the many other threats facing birds during the current biodiversity crisis, the impact of artificial lights can be mitigated by an easy change to our own behaviour: the flip of a light switch.

In spring and fall we should turn off our outdoor lights at night. With the lights out, we can take the opportunity to stand outside and listen to the night sky. We’ll hear the sounds of a billion animals moving across the continent with less distraction from our light pollution.

Dan Mennill, Professor and Associate Dean of Science, University of Windsor

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Forget smart cities (for a minute), we need to talk about smart farms




There’s a lot of talk about digital technology and smart cities, but what about smart farms? Many of us still have a romantic view of farmers surveying rolling hills and farm kids cuddling calves, but our food in Canada increasingly comes from industrial-scale factory farms and vast glass and steel forests of greenhouses.

While the social and environmental consequences of agri-food industrialization are fairly well understood, issues around digital technology are now just emerging. Yet, technology is radically transforming farms and farming. And while different in scale and scope, technology is playing a growing role in small and organic farming systems as well.

In reality then, your friendly local farmer will soon spend as much time managing their digital data as they will their dairy herd. The milking apron is being replaced by the milking app.

The Canadian government is investing heavily in climate-smart and precision agricultural technologies (ag-tech). These combine digital tools such as GPS and sensors with automated machines like smart tractors, drones and robots in an attempt to increase farm profits while reducing pesticide and fertilizer use. GPS mapping of crop yields and soil characteristics help to cut costs and increase profits, so while seeds still grow in soil, satellites are increasingly part of the story. There’s no doubt that ag-tech may be promising for governments, investors and corporations, but the benefits are far less clear for farm owners and workers.

There is little research on the potential social impacts of ag-tech specifically, so a group of researchers at the University of Guelph conducted a study to figure out some of the likely impacts of the technological revolution in agriculture.

While changes in agriculture show promise for increasing productivity and profits and reducing pesticides and pollution, the future of farming is not all rosy.

Corporate control of many agricultural inputs — seeds, feed, fertilizers, machinery — is well documented. Agricultural land is also increasing in cost and farms are getting bigger and bigger. It is likely that digital agriculture will exacerbate these trends. We’re especially interested in what farm work will look like as the digital revolution unfolds.

Factory farms are the norm in Canada. Shutterstock

Marginalized workers are set up to lose

While rising costs are always a concern for producers and consumers, we have two main concerns about how the digital revolution is changing farm work in particular.

First, who owns all of the data being produced in precision agriculture? Farm owners and workers produce data that has massive potential for commercial exploitation. However, just who gets to harvest the fruits of this digital data labour is unclear.

Should it flow to those who produce it? Should it be something that we own collectively? Unfortunately, if smart farms are anything like smart cities, then it looks like corporate control of data could tighten.

Second, it’s very likely that ag-tech will lead to an even more sharply divided labour force. So-called “high-skilled” managers trained in data management and analysis will oversee operations, while many ostensibly “lower-skilled” jobs are replaced. Remaining on-the-ground labourers will find themselves in working conditions that are increasingly automated, surveilled and constrained. For instance, in fruit and vegetable greenhouses inputs are increasingly being controlled remotely, but migrant workers still do much of the planting and harvesting by hand. And, they do so under conditions of severe physical and social immobility.

There is a wealth of research documenting the vulnerable position of migrant agricultural workers from coast to coast in Canada and elsewhere.

If we don’t direct it in a humane way, the digital revolution in agriculture is likely to heighten these vulnerabilities.

The agricultural system was built that way

Our food system is built on centuries of Indigenous land theft, dislocation and the suppression of Indigenous foodways while relying heavily on exploitable (Indigenous, migrant and racialized) labour. Across North America, farm workers have long been excluded from basic labour laws, legal status and the right to unionize.

And now, increased productivity often relies on increased exploitation – just ask anyone working in a FoxConn factory. As a result, our current food system is rife with exploitative practices, from production through to distribution, with racialized immigrants bearing the brunt.

Meanwhile, there is evidence that automation tends to negatively impact already marginalized workers.

The digital revolution in agriculture has a double edge. Smart farms bring promise, but automation in agricultural production and distribution will eliminate many jobs.

Our concern is that the suite of jobs that remain will only deepen economic inequities — with more privileged university graduates receiving the bulk of the well-paid work, while further stripping physical labourers of their power and dignity.

There is no magic pill, but our governments do have options. Policy and legislation can shift the path of ag-tech to better support vulnerable farm workers and populations. In doing so, the looming issue of land ownership and repatriation must be addressed in Canada, with Indigenous nations at the head of the table alongside marginalized workers and farmers. Supporting pathways to farming and permanent residency for migrant workers, as well as training for digital skill-building can help to close more immediate gaps.

We need to ready ourselves for how radical transformations in food production and distribution will impact land prices, property rights and working conditions. Our folksy view of farming is due for an update.

Sarah Rotz, Postdoctoral Fellow , Queen’s University, Ontario and Mervyn Horgan, Visiting Fellow, Department of Sociology, Yale University and Associate Professor of Sociology, University of Guelph

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Scientists are beefing over which one of our senses is most important




HIf there is one thing Twitter has taught us, it’s that the world loves a question that sounds stupid, but actually has a profound and interesting answer. For instance, what would happen if the world suddenly turned into blueberries, as answered by physics recently. Or what colour is that dress?

In a similar way, perception scientists have recently been fighting it out on Twitter to answer the seemingly trivial question of: “which is the best sense, and why?”. The debate has opened up some surprisingly deep questions – like what actually makes a sense more or less valuable? And, are some senses fundamentally more important in making us human?

The question was also put to a poll. While most people would probably assume the obvious winner is vision, “somatosensation” – which we normally refer to as touch but technically incorporates all sensations from our body – took the day. But does this vote hold up when you take a closer look at the scientific evidence?

Losing your body

We need somatosensation to move successfully – seemingly more so than vision. While a big claim, it is arguably backed up by the rare handful of cases where this sense is lost. “Deafferented” patients are individuals who have lost most (or all) touch sensation, as well as the ability to sense the position (proprioception) and movement (kinesthesia) of their limbs. This may occur because the body attacks its own somatosensory nerves in post-infection autoimmune reaction, though in most cases the cause is unclear.

While there is no direct dysfunction in the patient’s motor systems, most sufferers cannot complete even the most basic of movements. That’s because the brain must feel the body’s starting position to create the right motor plan, and needs sensory feedback to know if the plan was executed successfully.

Despite these barriers, one patient, dubbed “IW”, shocked medical experts by regaining the ability to walk. He achieved this feat by meticulously planning what muscles to contract, in what order before moving – then staring at his limbs to track his success. This strategy is highly cognitively demanding, and not at all the norm, with most patients bound to wheelchairs.

Many foodies might think that taste gets their vote for top sense. However, those who have tried eating after dental anaesthetic can attest to the risks and difficulties of eating without somatosensation – a challenge described by the deafferented patient “GL” in the scientific literature.

Another subcomponent of somasensation is the vestibular system, which is critical in keeping us upright. If you have ever been motion sick, you have a tiny insight into what happens when this critical system goes awry. In short, your eyes tell the brain you are moving, but your vestibular system says you are still – causing a conflict that can lead to vertigo, nausea and loss of balance.

Pain and temperature perception also get lumped in with somatosensation, failing to fit into any other category. Being born without sensitivity to pain is rare (around 45 documented cases) and highly dangerous. Some experts speculate the incidence may actually be largely underestimated, as sufferers don’t survive long enough to be documented. This is because pain tells you something is directly impinging on your body in a bad way, and you better react fast. Patients must self-check multiple times daily, to prevent infection from cuts they haven’t noticed.

Sebastian Kaulitzki/shutterstock

Touch forms a core part of our humanity. It is the first sense to develop in a fetus in utero, and some suggest the integration of sensations related to the body may form the basis of our fundamental self consciousness.

The touch of another can also reduce anxiety, influence our behaviour, shape brain development and reduce brain responses to pain in babies. We even have a dedicated set of nerves that preferentially process “social” and “emotional” touch.

Vision versus touch

On the other hand, looking from a neuroscience perspective, it is easy to see (no pun intended) why vision almost won the poll. The brain seems to have a vision focus. The primary brain area for processing visual stimuli, the visual cortex, takes up the largest area of any individual sense. Partly because of this vast processing resource, vision is the most acute sense we have for various kinds of discrimination.


The high reliability of vision means that if there is a conflict between what two senses say, vision will typically warp our final perception to be in line with the visual information. In the famous rubber hand illusion, stroking a realistic dummy hand in front of a person (and hiding their own hand) can make the person feel as if it is their own hand that is being stroked – with vision hijacking their sense of touch. Similar things happen when you conflict hearing with vision.

Vision also allows reading, writing and art. You can see the faces of your loved ones, or danger coming from far away. But maybe we only think vision is so crucial because it is at the very forefront of our daily experience. As Kevin Wright, an assistant professor of neuroscience at the Oregon Health and Science University, who posted the best sense poll, states – people may simply perceive the loss of vision as being more life affecting because “we are more aware of our vision as opposed to our somatosensory function”.

And the rest…

So are the other senses really less important? Our sense of smell is incredibly ancient and complex. If order indicates anything, smell is a form of chemoreception which is thought to have been the first “sense” to evolve in our early multicellular ancestors. Smell is the only sense that bypasses our brain’s sensory relay system –- going straight to the cortex for processing.

Ancient but crucial. welcomia/Shutterstock

Smell works together with taste to stop you eating spoiled or poisonous foods. Smell is also strongly linked to autobiographical memory, therefore forming a core part of the processes that maintain our identity. And hearing is better than both touch and vision for detecting danger coming up behind you. And it is certainly better than vision in the dark. And no hearing, no music. Enough said.

At the end of the day, somatosensation gets my vote because it keeps me upright, moving and alive – more so than the others. Looking to the future, however, I am excited to see how sensory substitution technology might upend our assessments of what sense is more or less important. As science reveals, for instance, that with the right device you can learn to see with touch or sound.

Harriet Dempsey-Jones, Postdoctoral Researcher in Cognitive Neurosciences, UCL

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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How clean is your city? Just ask the bees




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Honey can carry clues about where pollutants come from. (Shutterstock)

Kate E. Smith, University of British Columbia; Diane Hanano, University of British Columbia, and Dominique Weis, University of British Columbia

There’s a good chance you live in a city — or will soon. According to estimates by the United Nations, two out of every three people will live in an urban area by 2050.

The environmental impact of such rapid urbanization is a global concern. Traditional methods of monitoring pollution such as soil and air sampling can be expensive and time consuming.

We need new tools to track heavy metals and other pollution. So, we came up with a novel approach — honey.

A sweet beginning

It all began with a question. Julia Common, the chief beekeeper at Hives for Humanity, a Vancouver-based, non-profit organization of urban beekeepers, was asked repeatedly, “How clean is the honey from downtown Vancouver?”

Sampling honey from hives to test for environmental pollutants. Kate Smith, Author provided

Hives for Humanity manages about 200 hives within Vancouver. They’re on rooftops in the bustling city centre, near city gardens, in residential back yards and on farms in Delta, one of British Columbia’s major agricultural hubs. The organization doesn’t only produce honey, they also manage several therapeutic beekeeping programs.

To help answer this question, Dr. Dominique Weis, the director of the Pacific Centre for Isotopic and Geochemical Research, measured a suite of trace elements (including lead, titanium and cadmium and others) in some of the honey from Hives for Humanity. The honey was clean, well below the worldwide average for heavy metals like lead.

But when Weis started looking more closely at the data, she realized that the honey carried additional clues about where the metals came from — and could be linked to land use and human activity in the immediate vicinity of the hive.

Bee-sourcing science

When honeybees forage for pollen and nectar, they also pick up dust and other small particles, and carry it back to the hive where it is incorporated into the honey and other hive products.

Since bees rarely forage more than two to three kilometres from their hive, the honey provides a chemical snapshot of the environment surrounding the hive. This phenomenon has been exploited in a number of studies to assess not only the levels of certain metals in the environment, but also the effects of pesticides and the environmental impact of nuclear fallout.

Our study showed that honey collected from areas of higher urban density contains elevated levels of metals, including tin, lead, cadmium, copper and zinc. Antimony, for example, is elevated in honey from downtown Vancouver, relative to suburban and rural honey, presumably due to stop-and-go traffic, as antimony is a component in vehicle break pads.

Other batches of honey sampled from areas near the shipping port, showed higher levels of vanadium, which can be found in heavy fuel oils burned by large engines such as those on cargo ships.

Even though we could find these trace elements in the honey samples, the concentrations were too low to pose any health risk. An adult would have to eat more than 600 grams of Vancouver honey per day to exceed tolerable daily lead intake levels.

Fingerprinting honey

We also analysed the different forms of lead, called isotopes, found in the honey to see how land use influenced the type of lead found in the environment. This had been tried only once before, in Australia.

Because each source of lead has a characteristic isotopic composition, this approach is a little like fingerprinting the lead. Honey from industrial or heavily populated sectors of the city has a different lead fingerprint than local, natural lead found, for example, in the rocks from the Garibaldi volcanic belt or sediment from the Fraser River. That means that the lead observed in honey from downtown hives is likely the result of human activities.

Vanadium can be found in heavy fuel oils like those used by large cargo ships. (Shutterstock)

Overall, the chemical signature in honey from any sector of the city reflects a combination of the botanical offerings that surround the hive, as well as other pollution sources associated with land use: traffic, shipping, rail yards and agriculture.

Monitoring change

The honey paints a comprehensive picture of current trace metal distribution throughout Metro Vancouver. In the future, we can look for variations, as the city grows and changes over the next century. Cities are dynamic and experience constant shifts in land use, population growth, aging infrastructure and climate change (especially coastal cities).

Because honey bees live where humans live, the method could be used anywhere hives exist. This makes it possible for cities around the world to harness the power of the honeybee, even if they lack more traditional environmental monitoring infrastructure.

Urban gardening and urban beekeeping are rising in popularity, which makes projects like these all the more amenable to community participation.

The benefit of engaging the community in the scientific process is that everyone gains a deeper appreciation for their environment and local ecology. That, like the honey in Vancouver, is a sweet outcome!

Kate E. Smith, PhD Candidate, University of British Columbia; Diane Hanano, Research Manager, University of British Columbia, and Dominique Weis, Professor, University of British Columbia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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