Get Sleepy: Sleep meditation and stories - The Sleepy Science of Bird Migration

Starting point is 00:00:00 Hey friends, for the best Get Sleepy experience, be sure to check out our supporters feed Get Sleepy Premium for our free listening weekly bonus episodes and access to our entire catalogue. Now, a quick word from our sponsors who make the free version of this show possible. Hey friends, welcome to Get Sleepy. When we listen, we relax and we get sleepy. I'm your host, Thomas. As always, it's so special to have your company. The team and I feel so blessed to be able to help you sleep whenever you need us. We're all lucky to say that we absolutely love the work that we do here on Get Sleepy, and the fact that it resonates with you and hopefully positively

Starting point is 00:01:00 impacts your rest and well-being. Well that's all we could ever wish for. So thank you for lending us your company, right now, and anytime you tune in. Tonight we have a beautiful story written by Delaney. We'll be learning about the fascinating science of bird migration. Autumn is the season where many types of birds begin their annual journey, hundreds or even thousands of miles in search of cosier places to spend the winter months. So from the comfort of our beds, we'll follow their serene flight. The very best way to listen to Get Sleepy is on our supporters' feet, Get Sleepy Premium. There, you'll have access to our entire catalogue of over 600 stories and meditations, including extra long episodes and series compilations, and it's all completely out-free. Plus, every single Thursday, we release a

Starting point is 00:02:17 new bonus episode exclusive to the Premium Feed. Tomorrow night Vanessa will be reading to us, as she tells a simple story about an activity that may be familiar to many of you. It's about two friends unwinding, with a relaxing day of shopping. The first seven days of your premium subscription are free, so why not give it a try and see if you agree that it's the very best companion for a good night's rest. For more information on all of our premium plans, visit getsleepy.com slash support, or just follow the link in the show notes. Thank you for your support. Just follow the link in the show notes. Thank you for your support.

Starting point is 00:03:10 Before we hear tonight's story, settle into bed and make sure you're nice and comfortable. If you need to adjust your pillow or roll onto your side or back, now is a good time to adjust. And then settle in. Once you're ready, close your eyes. Take a deep breath in through the nose. And enjoy the calming sensation as you exhale back out. Let your shoulders loosen and relax. Unclench your jaw if you're holding tension there. And just gradually allow yourself to release any excess energy lingering in your body. Now, imagine a cool breeze flowing past your cheeks.

Starting point is 00:04:42 It rustles the leaves of a nearby tree. Gone are the greens of summer. The reds, oranges and yellows of autumn have taken their place. Just as your body and mind transition from wakefulness to sleep, this part of the world shifts to a time of somber as the year draws to a close. Bird sense the change and prepare for the journey ahead. And this is where our story begins. Every autumn, several billion birds across the northern hemisphere start to notice a change in their surroundings. The graceful swans living in coastal Alaska ponds begin to fluff up their feathers as the

Starting point is 00:06:21 water they glide across gets colder. Delicate finches make note of the shortening day length. As flocks of sandhill cranes forage for food in prairies, they may realize that the supply is dwindling. These realizations tell the birds that it's time to begin the annual journey known as migration. Bird migration doesn't happen all at once. We don't wake up one morning to realize that nearly half of the birds we have grown so used to seeing and hearing during the spring and summer months have packed up and fled. Instead it is a more gradual process, which makes it a little easier to say goodbye. One morning in early fall, you may lie in bed, reveling in your cozy blankets, and watching

Starting point is 00:07:50 the drops of condensation race down your window pane. Perhaps you take a moment to appreciate the trills and warbours of the birds in your garden before realizing that something is missing. The short, sweet chirps of the scarlet tannager are no longer uplifting the sounds of the early morning choir. A few days later, the sharp staccato notes of the ovenbird are no longer carrying the percussion section. These absences will continue until your mornings are only warmed by the sounds of the resident birds that choose to stick around or winter. They add a little extra wonder to the early morning moments that you enjoy. Perhaps while sipping coffee wrapped in a warm quilt before embarking on your day. As the flapping of their wings lifts them into the sky and carries them to a more suitable

Starting point is 00:09:31 sight for the winter, these migratory birds might whisper a bittersweet goodbye to the region Lake All Home for half of each year. They make a quiet promise to return to the area where they were born, thanks to their reliable navigational skills and memory. At the same time, they look forward to the warmth and abundance of food that await them elsewhere. Migration is the journey that some bird species embark on twice a year when the weather grows cooler. It's a cyclical journey and after a few months they will return to the area they came from in order to find a mate and breed during the summer months when food supplies our ample and the weather is warm. This behavior is typically observed in birds that breed in the northern hemisphere and most

Starting point is 00:11:04 species fly south. While picking up and heading to Costa Rica before a single snowflake has a chance to garnish their wings, sounds like a great idea. Migration can be a dangerous and arduous endeavour, but also a deeply rewarding one. About 40% of the world's bird species migrate, while the rest hunker down and spend their year in just one place. Throughout the autumn, those of us that dwell in the northern hemisphere can follow these patterns playing out in our own neighborhoods. neighborhoods. Perhaps one day, the loud honking of the Canada geese that resounds across your local park during spring and summer has blessedly disappeared. You might also notice that some of the more pleasant bird species are missing as well.

Starting point is 00:12:29 The flute-like sounds of the woodthrush and the brilliantly blue indigo-bunting that to have evaporated. So where did they go? After they've left the area where they were born and make their own nests, known as the breeding grounds, they are on route to the more southern region, called the Wintering Grounds. The breeding grounds are where birds spend their summer months, and it's important to understand their place in the crooks of tree branches. They weave their nests using a variety of materials, including leaves, twigs, grass and even strands of human hair. This is where they lay their eggs and raise their hungry, open mouthed chicks. Once the babies are big and strong enough to fled from their nests, the impending months of autumn approach, bringing with them cooler temperatures and a decline in the berries and insects that they have feasted on throughout the spring and summer.

Starting point is 00:14:29 The days become shorter and some intrinsic knowledge that is built into their DNA tells them that it is time to take off towards their wintering grounds. The region that abird chooses as their escape from winter woes, and the distance they travel, depends on the species and where they nest. The location of breeding grounds is of course a major determinant of wintering grounds. For example, most of the migratory birds that nest and breeding Canada and the United States every summer, will spend their winter months in Central or South America. Most birds that nest across Western Europe will spend their winters in Sub-Saharan Africa. in Sub-Saharan Africa. Australia and New Zealand are popular destinations for East Asian birds to post up the part of the year. Different species are capable of traveling varying distances.

Starting point is 00:16:07 Some fly a few hundred miles, while others fly over ten thousand. The most impressive long-distance migrant is the Arctic turn. This beautiful grey and white bird has a completely black head, making it look like it is wearing a dark cap. While it only weighs around four ounces, about as much as a deck of cards. This bird species flies from the Arctic Circle to Antarctica twice a year. Traveling from the most northern region of the northern hemisphere to the most southern part of the southern hemisphere requires a nearly 19,000 mile track. Another impressive migrant is the Kaliope hummingbird. These beautiful birds emblazoned with iridescent green feathers

Starting point is 00:17:30 and sporting jaunty purple chests are commonly seen buzzing and sipping around bird feeders and sweet smelling flowers like close of the mimosatri. Seeing these adorable birds sip nectar as they hover effortlessly in the air, few would believe that they could possibly be up for the challenge of long-distance migration. After all, they weigh just 3 grams, about as much as a penny. And yet, they fly 5,000 miles a year, going south through the rocky mountains in the fall, and heading north along the Pacific coast in the spring. Bird migration doesn't just mean traveling remarkable distances. It also requires that birds fly astonishingly high in the sky. The most notable high flyer is the bar-headed goose. Goose migration path takes it over the Himalayan mountains.

Starting point is 00:19:08 In order to make this journey, these birds must fly up to 5 and a half miles above sea level. These high-flying birds travel at such great altitudes that they have to keep an eye out for planes during their migration. Birds don't just travel amazingly far and high in the sky. They can also zip through the air at stunningly fast speeds. The speediest migrant is a small wading bird called the Great Snipe. They breed in Sweden and make their way to sub-Saharan Africa every year to pass the winter. This long migration of 6,000 miles is made in record time as the birds race across the sky at 60 mph. We grounded humans could never dream of keeping pace

Starting point is 00:20:33 with the snipes. The fastest known human, Usain Bolt, is able to run at 27 mph and he is only able to keep his impressive speed up for less than a minute. Next time you are in a car, traveling along at 60 mph, imagine this bird flying outside your window at exactly the same speed. Arctic turns, bar-headed geese and hummingbirds are just a few examples of migratory birds. There are at least 4,000 other species of birds that embark on similar journeys. That means that around 4 billion birds soar across the sky every autumn and return home to their breeding grounds every spring. Not all birds take the same root, but there are migrating hot spots that birdwatches make their own voyage to every year to see the glorious show of thousands of birds flitting through the air. Places like the Florida Keys and Point Reyes in California are especially well known to bird lovers. Before launching into their great journey across the ocean,

Starting point is 00:22:30 on the way to their wintering grounds, many birds need to take a quick break to gather strength. And these spots are a great place to capture gl of hordes of migratory birds. During their return to their breeding grounds in the spring, a blitz of migratory birds can be found in southern Texas near the Gulf of Mexico. For many birds, this is the first landmass that they will come across after leaving their wintering grounds in Central America. It's a wonderful sight for bird lovers and a welcome It's a wonderful sight for bird lovers and a welcome relief for the birds that have just flown for 18 hours straight as they passed over the Gulf of Mexico. There is even a well-known phenomenon referred to as birdfall out that can be seen on the

Starting point is 00:23:47 Texas side of the Gulf Coast every spring. Eager to rest their weary wings, thousands of birds of all different colours, shapes and sizes can be seen corigning towards the ground. But don't worry, the birds are safe. At times, this fallout happens because of bad weather. The birds choose to stop and wait as soon as they hit land in Texas, rather than trying to fly through storms and high winds while they're already tired. It's impossible for us humans to imagine the physical toll of flying for so long without taking a break. But once their journey over the water is done, they can finally refuel and rest on land, before lifting back up into the sky and continuing on towards their breeding grounds. Traveling these long distances so quickly and at such great altitudes is quite the feat.

Starting point is 00:25:28 So how do birds do it? First of all, it's important that they are well prepared. This means that during the weeks leading up to their migration, birds will gorge themselves on food and water. Late insects and berries with high lipid and carbohydrate concentrations that can be stored as fat and used as energy reserves during their great journey. It takes a lot of feasting to make this possible. To put it in context, hummingbirds must eat the human equivalent of 150,000 calories per day. Before migrating, birds don't just make a change in how much they eat, there's also

Starting point is 00:26:39 a shift in what they eat. Swift's are omnivores and typically seek out insects to snack on. But during the weeks leading up to their takeoff, they switch to a higher carbohydrate diet consisting mostly of berries. This allows them to double their body weight in just a couple of weeks. Despite their need for fat reserves, they can't be weighed down by any extra baggage. This means that the fat needs to be distributed efficiently. Many birds are actually able to shrink and grow their internal organs as needed and can absorb much of the added fat into their liver, kidneys and digestive tract. This extra fat is used as a source of energy during long flying stints, making it possible for the birds to shrink their organs to their original size, without having to break down their much-needed heart and wing muscles during fasting periods.

Starting point is 00:28:21 Birds are also able to adjust their sleep schedule during migration season in order to make their long, arduous journey possible. While some bird species, like owls, are nocturnal, many are diurnal, meaning they are awake during the day and asleep at night. However, this isn't the case during migration season. There aren't many chances to find a place to patch and fall asleep when there are oceans and mountain ranges to be crossed. To overcome this, it's believed that many migratory species have the capacity to sleep

Starting point is 00:29:23 while in flight. It's not your typical kind of sleep, however, as they must maintain some awareness to stay safe and continue flying in the right direction. Have you ever heard of the phrase sleep with one eye open? This is something birds can actually do. This allows one hemisphere of their brain to rest at a time. A phenomenon known as unihemospheric slow wave sleep. This impressive ability is believed to be used during migration as they fly for days without touching land. Flying for so long is also very physically demanding. So there are a couple of ways that migratory birds can reduce the amount of effort required

Starting point is 00:30:38 for flight. They are able to harness the power of the wind by catching a ride on tailwinds. A tailwind is defined as a with the wind blowing in the opposite direction, what about when the wind is blowing in the same direction as you? As you can certainly imagine, flying on a tailwind conserves energy. Think of what it must feel like to capture right on a strong tailwind. You no longer have to propel yourself forward. All you have to do is spread your arms wide and sail effortlessly with the wind. The breeze brushes across your cheeks and your weary body can finally rest. Another clever thing that birds do to conserve energy is something you've likely seen before.

Starting point is 00:32:19 Many waterfowl species, like geese and pelicans, travel as a flock. But the way they arrange themselves isn't random. They fly in an elegant and efficient V shape. The formation typically consists of one leading bird at the tip of the V, followed by a staggered arrangement of other birds either side, with each bird slightly behind and to the side of the one in front. This arrangement allows the birds to take advantage of aerodynamic benefits, effectively reducing air resistance and conserving energy. The flapping of their wings is even choreographed in a manner that demonstrates impressive intelligence

Starting point is 00:33:29 and teamwork. The bird in front leads the way, while the rest flap their wings at just the right time to catch the uplifting draft of wind created by the bird in front of it. It's estimated that birds flying alone expend twice as much energy compared to those that travel in a V formation. Now for the biggest question of all, how do birds know where to go? How are they able to travel to the same breeding and mating grounds year after year. It takes us humans, maps and GPS units to make those sorts of journeys. Yet birds can cross oceans and wind up exactly where they're supposed to.

Starting point is 00:34:47 Hummingbirds even remember every bird feeder that they pass on route to their destination. So, if you put out a hummingbird feeder last autumn, don't forget to fill it up again this year. Otherwise you may disappoint some hungry birds that rooted their migration journey in a way that allows them to visit your garden for a sip of sugar water. But how do they remember all of these locations? And how do they find their way between them? The answer to this question is complex and varies by species. The scientific community has studied this conundrum at length and still has not formed a complete conclusion. We may never know every aspect of a bird's navigational abilities, leaving a mysterious gap in our understanding

Starting point is 00:36:08 of the natural world. But through extensive research involving many different species of birds, we have uncovered some of the elements of their phenomenal sense of direction. The ability to migrate takes more than just physicality. These birds have extraordinary memories and navigational skills. If you ever heard the term bird brain to describe someone who isn't very smart, you're likely rethinking the accuracy of this jive now. One of the most important aspects of a good sense of direction is an animal's ability to orient themselves to recognize where they are.

Starting point is 00:37:15 Birds rely on certain landmarks in order to do this. For example, sea birds often follow the coastline to avoid getting turned around. Like sailors, many bird species rely on the position of the sun and the stars to orient themselves. The majority of bird species travel at night with the moon and stars charting their course. A clever study of indigo-bundings involved testing birds in a planetarium. Unsurprisingly, they flew to the north in the spring and flew in a southerly direction in the fall. The hypothesis that these lovely songbirds navigate by the stars was confirmed when the projection of the galaxy was turned off and the birds no longer favoured any particular direction. But birds use more than just celestial guidance. It's believed that many species have a magnetic sense that

Starting point is 00:38:49 we as mere humans can't even fathom. They can detect the strong magnetic pull of the and South poles, which helps to orient and guide them on their journey. The way that birds sense the magnetic pole of the poles varies by species. Pigeons, for example, have a small speck on their beaks that contains magnetite. Other species appear to have magnetic receptors in their eyes. While birds are thought to be born with much of the intrinsic knowledge that is required to migrate each year. There is likely a learning component involved as well. Young birds that are flying to their wintering grounds for the first time often don't recover

Starting point is 00:40:01 when they are thrown off course or are separated from their flock. However, older birds that have already made this journey several times can easily reorient themselves and still make it to their destination, even when things don't go as planned. This means that the complex instructions for migration are not just passed through the genetic code, they are also taught to each generation. As we begin to fill the chillier of impending winter, raise goose bumps on our arms, our feathered friends are just beginning their tropical vacations. The meadowlarks, finches and sparrows that are familiar to us during warmer months are just ending their long and arduous travels. After many days and many nights of flight, they are surely washed over with relief when

Starting point is 00:41:33 they see their wintering grounds below them. As they drift down from the sky, and land in a place that is much warmer and stocked with an abundance of food compared to the breeding grounds they left behind, they must know that they are finally safe and sound. Awaiting them is a great feast and a night of sound sleep perched on a branch. Many of us feel a slight sense of loneliness that we can't quite put our finger on after the birds have departed. The morning chorus of bird song outside our windows will have thinned, but we can rest assured that our feathered friends will be back as the welcome return of

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Get Sleepy: Sleep meditation and stories - The Sleepy Science of Bird Migration

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