European small birds’ miles high migration to Africa

This 2015 video is called Red-backed Shrike. Singing male. Lanius collurio.

From Lund University in Sweden:

Small birds fly at high altitudes towards Africa

August 6, 2018

A new study from Lund University in Sweden shows that small birds migrating from Scandinavia to Africa in the autumn occasionally fly as high as 4,000 metres above sea level — probably adjusting their flight to take advantage of favourable winds and different wind layers.

This is the first time that researchers have tracked how high small birds fly all the way from Sweden to Africa. Previous studies have successfully logged the flight height of larger migratory birds.

“We only followed two individuals and two species. But the fact that both of them flew so high does surprise me. It’s fascinating and it raises new questions about the physiology of birds. How do they cope with the air pressure, thin air and low temperatures at these heights?” says Sissel Sjöberg, biologist at Lund University and the Zoological Museum in Copenhagen.

The aim of the study was to investigate whether the measuring method itself works on small birds, that is, to measure acceleration, barometric pressure (air pressure) and temperature throughout the flight using a small data logger attached to the bird.

The data logger was attached to two individuals of different species: the great reed warbler and the red-backed shrike. Among other things, the results show how long it takes for each bird to fly to their destination. The measured barometric pressure showed that the great reed warbler occasionally flies at 3950 metres, and the red-backed shrike flies at 3650 metres.

Both individuals flew the highest above ground across the Mediterranean Sea and the Sahara, but the shrike reached higher flight altitudes closer to its winter grounds in southern Africa.

Sissel Sjöberg thinks it is likely that other small birds fly as high, maybe even higher. But there is no evidence of that yet.

“In this study, we only worked with data collected during the autumn, when the small birds migrate to Africa. There are other studies that indicate that the birds fly even higher when they migrate back in the spring, but we cannot say for sure.”

The small transmitter was developed by technicians at the Centre for Animal Movement Research, CanMove, at Lund University. The study published in the Journal of Avian Biology is a collaboration between Lund University, the University of Copenhagen and the Nature Research Centre in Vilnius.


South African woman saving lions

This video says about itself:

One Woman’s Remarkable Journey to Protect Lions | Short Film Showcase

16 July 2018

Lion conservationist Moreangels Mbizah lives in South Africa, works in Zimbabwe, and studies in England. As one of the few female scientists in sub-Sahara Africa, Mbizah is committed to staying on the continent in order to carry out her research in Hwange National Park.

African electric fish, new research

This video shows Gnathonemus petersii fish.

From ScienceDaily:

A fish that subtracts its own electric signals to better ‘see’ through its murky habitat

July 11, 2018

The elephant-nose fish Gnathonemus petersii relies on electricity to find food and navigate through the obstacles riddling its native murky African rivers. On July 11 in the journal Neuron, Columbia University researchers present evidence that the fish’s ability to accurately “see” an “electrical image” of its surroundings requires it to filter out its own electrical interference.

“We needed to determine whether being able to predict its own electrical signals would help the fish better detect environmental cues”, says Nathaniel Sawtell, a neuroscientist at Columbia’s Zuckerman Mind Brain Behavior Institute. “So using both neural recordings and behavioral experiments, we showed that these predictions known as negative images actually do help the fish sense external signals related to hunting prey.”

As an electric fish, the elephant-nose fish has two specialized systems that help it sense its surroundings — a passive system attuned to the minute electric signatures of everything living in its environment, including prey, and an active system that voluntarily emits brief pulses of electricity. The fish uses these electrical pulses to both communicate with other electric fish and sense its environment by painting an “electric image” of it to aid in navigation.

“The fish’s own electrical pulses cause large neural responses that interfere with the passive system,” says Sawtell. “Our work shows how changes in neural connections produce negative images to cancel out this interference.”

While earlier studies speculated that the elephant-nose fish might generate these negative images, no evidence had existed to directly demonstrate their functional importance. But the authors showed that delivering a drug that interfered with the formation of negative images essentially blinded the fish to external electrical signals.

“An important part of this work has been the integration of experimental and theoretical approaches to understanding neural circuits”, says Sawtell. “From here, we’re trying to take the lessons we’ve learned from the electric fish and apply them to related systems, including the mammalian cerebellum and auditory system.”

Zebras, why their stripes?

This video says about itself:

Striped Survivors [Zebra Documentary] | Wild Things

27 January 2018

The promise of rain draws zebras across east Africa. The crew follows the zebras as they migrate to find an area full of grass and vegetation.

From Lund University in Sweden:

Stripes may be cool — but they don’t cool zebras down

July 6, 2018

Susanne Åkesson, a biologist at Lund University in Sweden, refutes the theory that zebras have striped fur to stay cool in the hot sun. That hypothesis is wrong, she and her colleagues show in a study recently published in Scientific Reports.

There has been an ongoing discussion among researchers, dating back to Darwin, on why zebras have their signature black and white stripes.

One of several theories is that it keeps them cool in the sunshine. The black stripes get warmer than the white areas, and the theory states that this creates small vortexes when the hotter air above the dark fur meets the cooler air above the white fur. According to the theory these vortexes works as a fan to cool the body.

To test this theory, the researchers filled big metal barrels with water and covered them with skin imitations in different colours: black and white stripes, black, white, brown and grey. They then placed the barrels in the sun and later measured the temperature in each barrel. Not surprisingly, the black one was the hottest and the white one the coolest. The striped and grey barrels were similar, and in these the temperature did not go down.

“The stripes didn’t lower the temperature. It turns out stripes don’t actually cool zebras”, says Susanne Åkesson.

Eight years ago she and her colleagues from Hungary and Spain presented another theory, where they claim that bright fur works as an optical protection against blood-sucking horseflies and other insects that bite. Horseflies are attracted by polarised light, the sort of light that appears when sunbeams are reflected on a dark surface. If the sunbeams are reflected on a white surface there will be no polarised light — hence the protection.

Two years ago Susanne Åkesson, the Hungarian physicist Gábor Horváth and their colleauges were awarded with the Ig Nobel Prize for their research on polarised light, horseflies and why these blood-sucking insects bother dark horses a lot more than they bother white horses.

Which European white storks will migrate to Africa?

This 2012 video from Germany is called White Stork on the nest (Ciconia ciconia).

From the Max-Planck-Gesellschaft in Germany:

Scientists can predict which storks will migrate to Africa in autumn and which will remain in Europe

May 24, 2018

For little Louis, it is the most exciting day of his life: just six or seven weeks ago, the young stork came into the world on a birch tree in Radolfzell on Lake Constance. Up to this day in June 2014, he has only known his parents and three siblings. But suddenly strange beings have appeared at the nest and are holding the four small white storks captive. They are Andrea Flack and Wolfgang Fiedler of the Max Planck Institute for Ornithology and the University of Konstanz. In the coming years, the scientists will learn from Louis and other young storks that, on their migrations south, storks follow other storks who are particularly good at exploiting thermals, allowing them to flap their wings as little as possible as they fly. The efficient fliers migrate to West Africa, while the others spend the winter in southern Europe. From their data, the researchers can tell which storks will fly where just ten minutes after the birds take off.

For days, Andrea Flack and Wolfgang Fiedler have been visiting storks’ nests on the western shore of Lake Constance. The aerial ladder of the fire brigade raises them to the stork nests at lofty heights so that they can strap small tracking devices onto the backs of the nestlings. The aim is to follow Louis and 60 other young storks on their migration. The instruments, which weigh less than 60 grams, record the GPS coordinates of the birds’ location. They also measure the animals’ movements using accelometers. This allows the researchers to determine whether and, if so, how the birds are moving.

For Louis and his nest mates, the harmless procedure is over in just a few minutes. Fully engaged in perfecting their flying skills, it is likely that they very soon forget the strange encounter with the scientists. For the researchers, however, the work has only just begun. From now on, they will collect and evaluate huge volumes of data, because the tracking devices log the storks’ GPS coordinates every second for two to five minutes every 15 minutes, and this for weeks. Once a day, the devices send a text message containing the location and movement data via the local mobile network, just like a mobile phone.

The data then flow automatically into an online database called Movebank, a free-to-use online platform developed by researchers led by Martin Wikelski, which allows scientists to log animal migrations anywhere in the world. Because the storks around Lake Constance fly all the way to West Africa for the winter, the mobile network costs would be enormous, given the immense volumes data involved. Andrea Flack therefore follows the birds by car all the way down to Barcelona to download the data once a day using a base station. In Africa, the devices log data at longer intervals to reduce the amount of data generated.

A mobile phone for storks

Louis, too, was fitted with his “mobile phone” on that day four years ago. As it turned out, he was the first among his nest mates to travel south. He joined a group of 27 other tagged storks. After five days of flying, 17 of them were still together.

Louis first skirted the Alps past Bern towards Lake Geneva and crossed the Rhone south of Lyon. On the evening of 23 August, he reached Montpellier on the French Mediterranean coast and then on the following day flew along the coast towards Spain. He crossed the Pyrenees and spent several weeks on a landfill site a hundred kilometres northwest of Barcelona. He then flew to an area around Madrid and spent the winter there at a landfill. He remained in Spain until the spring of 2016 and returned to Germany in March 2016.

Searching for thermals

Never before have researchers tracked a group flight of storks as meticulously as Louis and his peers. The scientists of the Max Planck Institute for Ornithology and the University of Konstanz have now published the results of Louis’ and his peers’ voyage. The data from the thousand-kilometre stage show how a bird’s flight performance, social behaviour and global migratory route are interlinked.

Thanks to a sophisticated analysis of the GPS data, the scientists have found that there are leader birds within groups of migrating storks. They lead the group to areas with favourable thermals, where the birds are literally sucked up by the rising warm air. This allows them to glide farther and avoid active flapping flight to save energy.

Efficient flyers lead the way

Detailed analysis of the high-resolution GPS data shows that the flight paths of the leader birds are more irregular. “They are the ones who locate the thermals and search out the most favourable areas within them. “As a result, they have to adjust their flight paths repeatedly”, explains Máté Nagy, who analyzed the data from the trackers. The follower birds benefit from the leaders’ explorations and can soar upward in more regular trajectories. “When travelling to the next thermal, follower birds are a bit slower and lose altitude faster. To avoid falling behind the group, they must flap their wings more and leave the thermals before reaching the top.”

However, a stork’s flying skill is not only linked to its position within the group. How much it flaps its wings also predicts where it will spend the winter. Animals that flap their wings a lot do not fly as far as those that flap less. Louis, for example, is a rather mediocre flyer. For him, it is better to spend the winter in southern Spain, especially since he can find enough food at the landfill site there.

Tour group with social structure

The situation is entirely different for Redrunner, another individual of the 27 tagged storks. He is one of the leaders of his group, and, therefore, manages to minimize his wing beats. He overwinters in North Africa. While Louis covered more than 1000 kilometres on his 2014 journey, Redrunner covered nearly 4000 kilometres. “The flight characteristics are so central to the birds’ position within the group that we can predict just after a few minutes of migration flight whether it will spend the winter in Europe or fly on to West Africa,” explains Andrea Flack.

This is the first time that humans have been able to observe the group behaviour of storks on their journey across Europe to Africa in such detail. The collected data show that storks fly in socially structured groups, which are largely determined by the flying skills of the group members. “A stork’s route and destination depend, among other things, on how efficiently it can fly,” says Martin Wikelski, Director at the Max Planck Institute for Ornithology and Honorary Professor at the University of Konstanz.

Back in Germany

Since then, Louis und Redrunner have repeated their journey every year — and always with the same destination: Louis has remained faithful to Spain and Redrunner to Africa. This year, Louis arrived in Germany on 9 March. Since then, he has stayed in Neudingen near Donaueschingen and has built a nest with a partner on the local town hall. Redrunner also returned from Africa a few weeks ago. He has taken up residence in the town of Münzenberg between Frankfurt and Giessen.

Now four years old, they have both survived the most dangerous phase of their lives, as 75 percent of young storks die in the first year. Now they are past puberty and may breed this year for the first time. If the two storks continue to successfully avoid all dangers, it is likely they will have a long life and will continue to make their long journey for the next 30 years.

Assuming that the two are still migrating, the researchers will no longer have to follow them in a car. The Icarus Initiative launched by Martin Wikelski will be launched in August, after which the tracking devices will transmit their data to scientists around the world via the International Space Station. Researchers will then be able to track the birds around the clock in real time.