Imagine a picture from the 16th century showing fishermen pulling a net full of swallows from a frozen lake. It might make you think that swallows hibernate underwater during winter. But guess what? They don’t! For a long time, people believed that birds hibernated or disappeared to mysterious places during the cold months. Some even thought birds flew to the moon for winter!
It wasn’t until around 1900 that people started figuring out where birds actually go in winter. A clever Danish teacher came up with the idea of putting small aluminum rings on birds’ legs. When these birds were spotted again, it helped map out their journeys. For example, a White stork with a ring from Hungary was found in South Africa, proving that birds travel long distances.
However, these rings only showed where birds were at certain times, not their entire journey. To learn more, scientists needed better technology.
Fast forward to more recent times, and scientists have used technology to track birds. They once attached a transmitter to a bald eagle in Maryland, which sent signals to satellites. This helped reveal amazing journeys, like the bar-tailed godwit flying 11,000 km from Alaska to New Zealand in just eight days without stopping!
But there’s a catch: these transmitters are too heavy for small birds. So, scientists turned to GPS recorders, which are lighter because they only receive signals. Yet, even these are too heavy for the tiniest birds.
Thankfully, scientists found a clever solution. They use tiny devices called geolocators, which are as light as a raisin. These gadgets don’t send signals; instead, they record light levels, time, and other data. Scientists have to catch the birds again to get the information, but it’s worth it!
With these geolocators, scientists discovered the Great snipe’s incredible journey. This bird, weighing about 170 grams, flies from Sweden to Central Africa in just three days, zooming at 95 km per hour. And then there’s the Arctic tern, known for its epic round-trip between the Arctic and Antarctic. It turns out they travel over 80,000 km each year, using winds to help them along. Over a lifetime, an Arctic tern can fly more than 2.5 million kilometers—enough to go to the moon and back three times!
So, while birds aren’t hibernating in lakes or flying to the moon, their real journeys are just as fascinating and impressive!
Use a world map to trace the migration routes of different bird species mentioned in the article, like the White stork and the Arctic tern. Mark their starting points and destinations, and use different colors to represent each species. This will help you visualize the incredible distances these birds travel.
Design a poster that highlights the journey of one bird species. Include interesting facts, such as the distance traveled and the time taken. Use drawings or printed images to make your poster visually appealing. Share your poster with the class to teach others about bird migration.
Imagine you are a scientist tracking birds. Create a diary entry or a short story from the perspective of a bird wearing a geolocator. Describe the journey, the challenges faced, and the landscapes seen. This will help you understand the importance of tracking technology in studying bird migration.
Using materials like clay or cardboard, build a model of a geolocator. Explain how it works and why it’s useful for tracking bird migration. Present your model to the class, highlighting the technological advancements that have made it possible to study even the smallest birds.
Choose a bird species not mentioned in the article and research its migration patterns. Prepare a short presentation to share with the class, including where the bird travels, how far it goes, and any unique behaviors it exhibits during migration. This will expand your knowledge of the diversity of bird migration.
This 16th-century woodblock depicts fishermen pulling a large net filled with hibernating swallows from a frozen lake. If you haven’t heard about swallows hibernating at the bottom of lakes during winter, it’s because they don’t. For thousands of years, hibernation was one of the leading theories to explain where birds went between fall and spring. Another theory suggested that birds migrated far away for the winter, but people had no idea where they went. For instance, a pamphlet from 1703 even suggested they went to the moon.
The first real clues about where migratory birds actually go during the winter emerged around 1900, thanks to a Danish teacher’s technique of attaching marked aluminum rings to birds’ legs and then re-releasing them. Each recapture or sighting of a banded bird added a dot on the map, confirming long-distance migrations when a White stork banded in Hungary was found dead in South Africa. However, banding only provided information about specific points along a bird’s migratory path, not what happens between those points.
More recently, researchers gained a better understanding of these annual migrations when a bald eagle in Maryland was captured and fitted with a transmitter powerful enough to send signals to orbiting satellites. Satellite tracking revealed remarkable migrations, such as the bar-tailed godwit’s annual flight from Alaska to New Zealand, covering 11,000 km in about eight days without stopping. However, there is a limitation to satellite tracking devices: even with modern technology, transmitters powerful enough to send signals to satellites are still too heavy for small songbirds.
A slight improvement is using GPS recorders, which are smaller because they receive rather than send signals to satellites, but they are still too heavy for the smallest birds. Fortunately, scientists have realized that satellite tracking isn’t necessary. Instead, birds can be fitted with tiny light-level recorders, clocks, and memory chips, which together weigh as much as a raisin. These lightweight recorders don’t broadcast, so researchers need to recapture the birds to retrieve the data. They can then use ancient navigation methods to reconstruct the bird’s daily location during its journey: the length of each day indicates latitude, and the time halfway between sunset and sunrise indicates longitude.
These clever geolocators have revealed the world’s fastest migration: the Great snipe, which weighs about 170 grams, migrates from Sweden to Central Africa in just three days, averaging 95 km per hour. Another long-distance migrator, the Arctic tern, is known for its annual round-trip flight between the Arctic and Antarctic—an estimated 40,000 km. However, recent data from light-level geolocators show that terns actually travel more than twice that distance each year, possibly to take advantage of prevailing winds. This means that Arctic terns can accumulate over 2.5 million kilometers of flight in a lifetime—enough for three round trips to the moon. But as far as we know, they haven’t made it there yet.
Birds – Warm-blooded animals with feathers, wings, and beaks, most of which can fly. – Many birds migrate to warmer regions during the winter to find food and suitable habitats.
Migration – The seasonal movement of animals from one region to another for feeding or breeding. – The migration of monarch butterflies is a fascinating journey that covers thousands of miles.
Technology – The application of scientific knowledge for practical purposes, especially in industry. – Scientists use technology like GPS to track animal migration patterns.
Geolocators – Devices used to track the movement and location of animals by recording geographical data. – Researchers attach geolocators to birds to study their migration routes.
Journeys – Trips or travels from one place to another, often involving long distances. – The journeys of sea turtles across the ocean are crucial for their survival and reproduction.
Signals – Transmissions or indications used to convey information, often in the form of waves or pulses. – Animals like bats use echolocation signals to navigate and find food in the dark.
Distances – The amount of space between two points, often measured in units like miles or kilometers. – Migratory birds can travel vast distances without stopping, sometimes crossing entire continents.
Lightweight – Having little weight; not heavy. – The lightweight design of a bird’s skeleton helps it to fly efficiently.
Tracking – The process of observing and following the movement of animals or objects. – Scientists are tracking the movements of whales to understand their migration patterns better.
Hibernate – A state of inactivity and metabolic depression in animals during winter. – Bears hibernate in dens during the cold months to conserve energy when food is scarce.
