When the Night Returns, Animals Take Over

The lockdowns of 2020 and 2021 opened up a gap in all of our lives that no one had ever imagined possible. Before the menace of a terrifying virus, cities came to a standstill. Nearly three billion people had to suddenly lock themselves away in their homes. From one day to the next, the streets were emptied, leaving behind a disturbing silence. But not for everyone. Very often, wild animals filmed in urban environments are used to humans who have fed and raised them since birth like their natural parents would have done. So we get beautiful and spectacular pictures which are not always realistic. But in 2020, reality would go beyond fiction. City dwellers from around the world filmed what were once unimaginable scenes with mobile phones. Peacocks, goats, deer, wild boars, foxes, weasels, and many other wild creatures walked down the roads as if they were alone in the world. More interested than disturbed by this universe where humans seemed to have suddenly disappeared. Lockdown brought about a slowdown of human activity such as the modern world has never known. Become unnecessary, many lights were turned off in towns, suburbs, and even in the country. The darkness that came about revealed the value of a complete black night for wild nature, even if in some places this was already known. In Israel, hares took up love fighting. And in Australia, there were no holds barred. On the empty beaches, as in the towns, wildlife returned. In Brazil, during the 2020 lockdown, hundreds of baby green turtles were born on the beaches that were usually crowded and lit at night. In Thailand, 11 leatherback turtle nests were found on a beach where they had stopped coming because of tourists. In Indonesia, India, and Turkey, a record number of hatchings were recorded on beaches forbidden because of lockdown. This hadn't been seen for over 20 years. Once very abundant on Reunion Island, turtles practically disappeared during the last century because of fishing and the urbanization of the coastline. None of the animals came anymore to lay their eggs. So the arrival of a green turtle is always a great moment. Gabi is one of the returning residents. She waits for night to wander the beach. She comes because this is the only beach on this part of the coastline which is completely dark, because before we started the restoration program for the egg-laying beaches, it had been at least 60 years since there'd been eggs laid at Saint-Leu. She needs darkness. A very dark beach. And there are many beaches with no public lighting. This is practically the only one on this part of the coast. Landscaping and revegetating the beaches of Reunion Island is the holy grail of Stéphane Ciccioni, oceanologist and director of Kelonia, a turtle protection center. This vegetation will allow the turtles to recognize the beaches which are good for egg and they will create a screen as well to limit and protect against light pollution from the human constructions behind the beach. The beach in 89, before we started the program, there was nothing on the beach, just some casuarina trees. And then here in 2018, the vegetation is already well developed. Plantations have to be made with precaution, as the turtles have a special relationship with beach vegetation. The smell of the plants is a reference for them to identify the sandy beaches which are best for egg laying. To reduce light pollution, LED lights only light the beach carpa. On the seaside, a deflector stops the light and leaves the sandbank in darkness. Gabi has dug a 70 centimeter deep hole and she lays 100 eggs in it, fills up the hole and leaves the beach. There are only two turtles which lay eggs on Reunion Island, Gabi at Saint-Lure and Emma at Saint-Paul. So it's really an extremely fragile situation. Protecting the nests is important because it's thanks to those nests that the population can regenerate, even if that takes 20 or 30 years. Emma comes in turn to lay her eggs before taking to the ocean for several years. Marine turtles go back to the sea relying upon their vision. The white foam, the light upon the water of the moon or of the starry sky make the sea the most luminous horizon. Artificial lighting disorients them. While the adults can still find their way, this isn't the same for the newborn who have no experience and limited strength. Each year thousands of them around the world attracted by distracting lights become lost and die of exhaustion. If we want to help the reproduction of marine turtles on Reunion Island, there absolutely have to be beaches suitable for egg laying and so to limit artificial lighting and human occupation of the beaches at night as it was possible during lockdown. Lockdown shone a light, as you might say, on the necessity to preserve what remains of the world's darkness. Migrating birds are particularly sensitive and clearly more affected by strong lights. Two-thirds of them migrate at night. They take paths that are well indicated by the lights of the moon and the stars. On Reunion Island from April on, the year's young petrels play out the destiny of their species. These seabirds born on the rocky heights of the island and which have never flown, throw themselves out into the emptiness to find the ocean. Usually urban lights and especially stadium lights attract them. They land far from water and remain on the ground completely lost. Light-blinded and stuck to the ground, these superb ocean birds are at the mercy of roaming dogs. The main reproduction site of petrels are the steep cliffs of Grambanar, one of the highest summits of Reunion Island, touching the sky at 2,900 metres of altitude. Six hours' walk is needed for scientists that monitor the colonies to reach the nesting zone. COVID-19 stopped any such mission for many months and researchers are worried that predators will have decimated the young population. Ah, a petrel's body. Yes, it's a chick. That's typical predation. Only the wings remain and all the flesh is gone. The nests are hidden in holes in the rocks and only a practiced eye can spot them. Yes, you can see the feathers there. I'd say that's a chick. Oh yes, you can see it. Burrow 137, one chick. This three-month-old young chick is larger than an adult because its parents have fattened it to be able to face a sea voyage of over three years. After five years' absence, it will return to its birthplace to reproduce. It will pick a partner to whom it will be faithful for all of its life. The couple choose a hole and make their nest. The species, of which remain only a few thousand couples, is still not well known. It is known that the female only lays a single egg each season, which makes the descendants extremely vulnerable. To understand the behaviour of this species in danger of extinction and essentially nocturnal, researchers use infrared cameras. A daring rat benefits from the absence of the parents to steal an egg. Here we're at an altitude of 2,600 metres and it's from here that the young petrels take flight to make their first migration. They leave in the dark of night, directing themselves by the light of the stars and the moon on the ocean, which they have straight before them, and from that it's easy to understand that the lights of the town can distract them from their path. To save the species and to make the departure of the young easier, Reunion Island began, over a decade ago, an operation to fight against light pollution called Nights Without Lights. Turning off most of the powerful projectors which light up sports grounds for night-time training has saved a large number of birds. But despite the reduction in lighting, volunteers of the Ornithology Studies Society of Reunion Island still save each year between 2,600 and 3,600 individuals. Because of their long wings and their palmed feet, it's impossible for them to take off from flat ground. Despite Nights Without Light, we still see that there are birds which fail, but with lockdown a lot less because the sports grounds, stadiums and other lights are turned off, and so we suppose that there are less birds that fail. In any case, we get a lot less reports. When they hit the ground, the young petrels often break a wing, which is the first thing the volunteers check for. A recovery centre has been created to look after them for the time it takes them to heal. The powerful pointed wings of these long-distance travellers are fragile. Here, they are cared for, watered and fed. Once they've been fixed up, they are released, and their long voyage can finally begin. The light footprint of urban and industrial areas continues to grow and to become more intense. Their lights disturb migrators, and blinding skyscrapers are so many traps of glass and steel along the ways of the birds. It is estimated that as many as a million birds die each year after a collision with a building. Hong Kong produces one of the worst human pollutions of the planet. In places, the night sky of the peninsula is a thousand times greater than the world average. The city of New York pays homage to the Twin Towers attack in light. Studies have shown that these powerful beams, visible from over 100 kilometres around, upset the migration of thousands of birds leaving the Great Canadian North to winter over in South America. Everywhere, over-lit zones are numerous, including in the countryside. Farms are lit at night to accelerate growth outside the ground and out of season. In the Brittany countryside, immense greenhouses are lit either with yellow lamps to favour flowering, or by red and blue LEDs to produce a violet light to increase gains. Here, we are 20 kilometres away from Lyon, and you can, however, see the halo of light which spills out well away from the city. And when you try to measure the intensity of darkness in the sky, you can see it's 17.04. That's extremely luminous, because a dark night should normally be around 22. The higher the number on the light meter, the darker the sky. In the Lyon CNRS laboratory, Thierry Longagne is studying the influence of light pollution on toads. The visual ability of toads is 1,000 times greater than our own, so they're very sensitive to light. For his experiments, he needs petrarchans who have had no light pollution. For that, Thierry goes to find them in a steep walled valley over 100 kilometres from the city. We'll take a look to see what the light level is. 21.02, that's a pretty dark sky. At the start of the reproduction period, hundreds of male toads leave the forest to go to the ponds. The females, much less in number and much larger, also go to the pools where they will lay their eggs. The love fest is general and often becomes confusing. Males jump on other males. An impassive female puts up with several simultaneous assaults. It is this unlimited sexual frenzy which Thierry uses to evaluate the influence of light pollution. Toads exposed to very low light intensity continue to mate. In another room, the toads are exposed to higher light intensity. Equivalent to the light halo found 30 kilometres outside the city. Here we see that males exposed to light pollution have difficulties mating with the females. They have problems hanging on. And we've showed something more serious, which is that this affects the fertilisation rate of the eggs, and so the population is at risk of declining afterwards. For toads, like for humans, light pollution affects the rhythm of activity, sleep quality and consequently biological secretions which are founded on the biological clock. The team recently made a worrying discovery. Light pollution affects the expression of genes in the common toad, and in particular genes linked to immunity. And so light pollution could bring about a collapse of the population. Unfortunately, toads are already in a major decline. Hundreds of thousands are dying every year, crushed on our roads. Every spring comes the clarion call of the species. Males and females leave the forest, cross the asphalt and hurry to the ponds where they give themselves over to a fecund bacchanal. The animals live by night, and so are used to having very, very little light to live by. And when they are blinded by headlights with very strong light intensity, they'll probably stay blinded for hours before their vision returns to normal. The installation of fabric barriers prevents the toads from throwing themselves into a suicidal crossing of the road. Volunteers recover them and release them, safe and sound, in a pond where soon myriads of tadpoles will be born. In France, green toads and common toads are the main victims of the roads. But they're not alone. Barn owls hunt small animals and insects close to the lights of the road. Blinded by vehicle headlights, many are struck down in full flight. The greater horseshoe bat, a bat of 30 to 40 centimetres wingspan, very common in Europe, flies just above ground level. It also pays a heavy tribute to road traffic. Vehicle headlights raise an uncrossable barrier. Scientists have found that their hunting ground is considerably reduced by the illumination of a road or a path. The drop in road traffic during lockdown saved the hide of many animals. In Europe, it's estimated that death-causing collisions dropped by 30%. In the USA, where road traffic dropped by 70%, collision deaths of moose, deer, bears and other large wild mammals fell sharply in the same proportion. However, lockdown had no effect on another great killer of wildlife, the victims being insects, bats and birds. The warning lights on wind turbines and unwanted light pollution for locals attract insects and, indirectly, their predators. In Germany, it's estimated that 200,000 bats are killed each year in collisions with rotating blades. The flight of Chiroptera is slow, whereas the extremities of the blades can reach a speed of 1,500 turns per minute. In France, a team from the Museum of Natural History of Bourges meticulously inventories the remains of animals lying at the base of the wind turbines. Laurent Arthur is on a crusade against this scourge. Ah well, a common noctule and it's a male. One of the main victims of wind turbines in Europe which goes to join in the container, the result of three mortality surveys on just three wind parks. Pipistrelle, Lyson noctules, and each time that we find a body there are in reality 10 which don't get found. Those are the European statistics. In their lowest position, the blade extremities are 20 meters from the ground. That means right in the flight zone of a lot of bats. Here we have common noctules, two, three, and they're common pipistrelles. So there are the two species which are the most affected on the European scale which are coming around. Thanks to a thermic camera, Laurent and Amélie film the wind turbines to understand why the animals are so many to expose themselves to the blades. We know in relation to the mortality linked to wind turbines that it's multifactored. There's the light of the warning lights. Insects are attracted to that. The bats come to hunt and there's a correlation between the presence of the insects we find in the gullets of the bats dead at the feet of the wind turbines and the fact they're attracted by the machines. Europe has lost close to 80% of its insects in less than 30 years and this loss has brought about the disappearance of over 400 million birds. Amongst those responsible for this slaughter, scientists point out public lighting. Because they turn around lights without cease, insects die of exhaustion or fried by the heat of lamps. In Paris, the extinction of the giant peacock moth, the largest butterfly in France, is partly because of public lighting. As adults, they only live a few days without feeding and they only fly at night to mate. They direct themselves by the lights of the sky but are stuck in place by urban lights. Disoriented, they often crash against street lights that they mistake for the moon. This species, now protected, was common 50 years ago. Artificial lighting also causes destruction in the population of mayflies, insects which are the main source of food for many animals. During their natural cycle, males and females gather in clouds at night to mate in flight. But, attracted to public lighting, the females die and their eggs are lost. Many species of ephemera, which are the most ancient living insects, are now threatened. Artificial light doesn't just make mayflies fly off their heads, but also makes moths go mad, like the snout moth. Blackbirds sing in the dead of night, snails go a-hunting at a late hour, and barrack swans eat in the dark. Raccoons make pigs of themselves at the foot of street lamps, and bats scoff up large in flight. These free restaurants open all night cause unexpected effects. And so, Italian scientists have found that the volume of bat skulls living in an urban environment has increased since the 1940s. This growth is due to the fact that the street lights attract a number of big insects whose resistant shells can only be eaten by bats with the most powerful jaws. By the same mechanism, the pipistrelle, which doesn't mind the light, is favoured in relation to other species like the greater horseshoe bat, which can't stand light. Chiruptera, which hunt by finding their prey by echolocation, shouldn't be bothered by public lighting. However, light pollution affects bats the most of all mammals. Recent studies have shown that the lighting of buildings where bat colonies live has a negative effect upon the reproduction rate and the survival chances of the young. Chiruptera nesting in lighted buildings come out on average 45 minutes later than the others. However, it's at the start of the night that the most insects are available. In Holland, single lamps light an experimental forest. Kamil Spoelstra, from the University of Wageningen, is testing solutions here to reduce the bad effect of lighting on bats and other nocturnal flying creatures. Bats, like most nocturnal mammals, can't see red light very well, or almost no red light. So if they're flying around the light post here, for example, they experience this area here as like almost total darkness. Kamil has noticed that insects are clearly less agitated by red lights rather than around green lights. The most catastrophic lights are blue and white LEDs, where insects turn around them until they are totally exhausted. For flora, it's the opposite. Green light doesn't affect the plants, but red light stimulates their growth. Kamil and his team have therefore replaced white lamps with red lights on bridges and canal locks that have been deserted by bats since they were lit. Equipped with very sensitive captors, they record the echoes of chirrup terror to count them. How many bats are passing upstream? 100. So bats experience this red light probably the same as we experience UV light, ultraviolet light. We can't see ultraviolet light. So like if they fly in red light, they experience it as very low light intensity or no light at all. You should turn this infrared thingy... Wow, it's really warm, by the way. A little bit this way. Kamil records the behavior of the chirrup terror with infrared cameras. The results confirm that the hunting of bats isn't disturbed by red light, however bright it is. It's a different species. It's a ceratine. Is it possible to use red light more in urban spaces? People come from all over the world to the Fête des Lumières in the city of Lyon, which takes place in mid-December at the year's darkest. A technical study center allows realistic experimental testing of several lighting systems developed by industry. For several years, awareness of light pollution has increased. Lyon is a pioneer in public lighting. The city is innovating by lighting the banks of the river with green and red LEDs. Rotterdam, Utrecht and other cities are also launching new solutions for urban lighting. During lockdown, the streets and canals of Amsterdam were deserted to the great happiness of bats and other mammals. It's quite normal that in this town, reputed for its red light district, research is ardently pursued. Kamil Aspholstra and his team study the reproduction of birds under diverse lighting. The researchers were surprised to find that, contrary to humans in the hot district, red light led males to protect the virtue of the females. One of the effects we see on birds is that the females that breed in the boxes that we put close to the light are more monogamous. And we think it's because the males, they are active slightly earlier in the morning, and they guard the female from other males that want to mate with them. The lights of the City of Lights have driven off nocturnal hunting birds. 30 couples of tawny owls had been counted in 1995 in several parks and gardens in the capital. Most lodged in cavities and trees, which were falling in number. But starting in the 2000s, the tawny owls disappeared despite 50 designed niches which rested empty. Today, there are just a few rare couples in the woods of Boulogne and Vincennes. But this wasn't always the case. The tawny owls invested Paris during the curfew imposed on the capital in 1940. Follow the regulations. Extinguish lighting. Don't wait to be ordered. During the COVID-19 pandemic, the many curfews decreed around the world permitted many real-life experiments which could not have been undertaken otherwise. For a long time, lighting cities has been a guarantee of security. In the 18th century, the Champs-Élysées, then Chady, was a risky place. Since then, public lighting has continually increased, often for futile reasons. Nowadays, the lockdowns and curfews have shown up what is now called light pollution and its consequences upon ecosystems. The first measure taken by some local authorities against the mismanaged waste of light was to turn off public lighting at certain times and places. Darkness and curfews helped the return of inveterate and compulsive pilferers. But also curious strollers looking for opportunities. In South Africa, the hippopotami graze by candlelight. Knowing that strangers were benefiting from the shadow to visit their gardens, amateurs took up infrared cameras to see what they were dealing with. For several years, Lille has experimented with alternative lighting in some parts of the city. During the pandemic, access to the Citadel Park, the green lungs of the city installed at the merging of two rivers, was forbidden to the public and reserved for the ecologist Johan Tisson. During lockdown, there was a quite incredible change in nature. Animals nesting in unlikely spots, coots, waterfowl who nested at the edges of the paths along the banks. Usually with dogs, that's impossible. Lille undertook the restoration of the park's biodiversity with a project called Luceole. To limit lighting, the lights of some avenues and paths only light up when a human presence is detected by captors. Once the user has passed, the lights go out and fauna can move as it wants in the darkness. Beforehand, the permanently lighted paths cut up the park into islands which didn't communicate with each other. The number of species fell and reproduction dropped sharply. Now the LEDs change colour and brightness according to the season. When the fauna is at rest during winter, the colour is whiter. If they are in full activity, the colour is amber and orange. Near the Citadel Vauban, Johan and the team take stock of nocturnal insects and in particular moths. A white sheet lit by a projector attracts the insects which land on it. That's a nice male chaffer. Common chaffers can be seen a lot more in town. It's one of the first things to be affected by light pollution. It's not bad really. They're a species never seen before. In 2003 and 2009, these species weren't present and so that's a good sign. The return of the insects has brought bats after them. 11 species have been identified. The great marsh murrein, a rare species of Chiroptera, is back in the city zones, for example, in the covered Deul Canal. Now this zone is plunged in darkness again which has let the bats retake possession of the place and these places are a kind of paradise for them. Spiders, very numerous, are a choice meal for Chiroptera. In the reproduction period, some take up residence under the arches. Adapted lighting and the emplacement of dark corridors have helped the mixing and development of colonies. Few people in Lille know that their city of brick hides 175 hectares of ancient stone quarries. Here too, the Chiroptera are back. They hibernate in the galleries and leave them in spring. You see this light? Well, that's where the bats come out in the spring after six months hibernation. The awakening of the Chiroptera is dictated by their biological clock and the meteorological conditions. Once the signal is given, their body temperature passes from 7 degrees to 40 degrees in less than two hours. They go to the light well, then the outside dark corridors to hunt. Oh, there we are. They're resting for the day. It's a bit like hibernation. During their acrobatic, sinuous and rapid flight, the bats use up a lot of energy to feed. They recover by sleeping for 20 hours a day. For the moment, we have six species observed reproducing and in hibernation. The goal of preserving these quarries and these important sites for them is that their population is restored and develops over all of the Lille region. Several regions in Italy, the Czech Republic, Denmark, Germany, as well as the city of Tucson in Arizona have renewed their public lighting to better preserve biodiversity. Seen from space, light pollution appears in its dramatic vastness. Modifying artificial lighting to reduce that pollution will be long and costly. 20 dark sky parks, starry sky reserves, have been created notably in France, Germany, the UK, Canada and in the USA. Others are being created. The objective is to preserve areas of the sky from the light fog which comes up from urban zones so the celestial arch can be contemplated at night in all its starry splendor. The struggle against light pollution is still at its first phase. The few rare initiatives to reduce it have already proved their interest for wildlife. But it's urgent to accelerate this movement. In the plant world, the effect of this pollution is still little studied. But we know already that, as with animals, the biological rhythm of plants is also disturbed by lighting that is too intense. The parts of trees that are strongly lit at night keep their leaves longer, can have troubles flowering and early budding. The consequence being a great vulnerability to the arrival of frosts. Maybe the lockdowns have allowed, despite ourselves, an awakening of conscience to renew contact with a nature that is less luminous.