What's indicated by the pen: birds will help create autonomous navigation systems for drones

Scientists have studied how young migratory birds use a complex system of innate "beacons" to navigate during their first migration. Landmarks can be stars, Earth's magnetic field lines, or the length of daylight. The data obtained changes previously existing simpler ideas about the capabilities of birds and can be useful in the development of autonomous navigation equipment, for example, unmanned systems operating in the absence of GPS signals. For more information about how nature helps to create bio—inspired technologies, see the Izvestia article.

How birds navigate during flight

Researchers from the Zoological Institute of the Russian Academy of Sciences (St. Petersburg) and St. Petersburg State University studied the current work on navigation in birds and determined that their abilities are much more complex than previously thought, and they include a system of natural landmarks.

Schematic representation of the "clock and compass" concept in young migratory birds, showing how they move from breeding grounds to wintering grounds using an internal timing mechanism and landmarks

Photo: Utvenko et al./Frontiers in Physiology

In the laboratory, the authors modeled the conditions that the winged ones encounter when crossing the magnetic equator. The magnetic compass of birds is designed in such a way that they do not distinguish north from south, but can distinguish between the direction "to the pole" (in the Northern Hemisphere, this is the direction to the north) and "to the equator" (in the Northern hemisphere, this is the direction to the south).

When a bird flying south crosses the magnetic equator (here the Earth's magnetic field becomes horizontal, since the vertical component of the field is zero), it needs to switch from flying to the equator to flying to the pole. In real conditions, this is the South Pole, and it flies further south. Geographically, the magnetic equator runs close to the usual one, but deviates in some regions. For example, in South America it is shifted to the north, and in the Indian Ocean it is shifted to the south.

1. Autumn trans-equatorial bird migration. (A) Image of the Earth's magnetic field. (B) The direction of the magnetic field lines in the Northern Hemisphere during the autumn migration of birds towards the equator. (C) The direction of the magnetic field lines at the magnetic equator. (D) The direction of magnetic field lines in the Southern hemisphere during the autumn migration of birds towards the pole

Photo: Utvenko et al./Journal of Experimental Biology

Biologists placed young (not yet flown) marsh warblers (Acrocephalus palustris) and gray flycatchers (Muscicapa striata) in such an orientationally "blind spot" for two days and three nights. These species were chosen because they regularly cross the magnetic equator during migration from Europe to Africa. At the same time, the birds were unable to receive any other signals besides geomagnetic ones for orientation, for example, to see the location of stars or estimate the length of daylight. After they were held in the conditions of the magnetic equator, the authors checked the direction of their orientation in circular arenas — small cells in the shape of a cone.

Predatory Calories: how the menu of Moscow peregrine falcons will help their reproduction

Why is it important to increase the population of rare birds in a megacity

It turned out that both species retained the same orientation direction to the equator, that is, to the south. In previous experiments on garden warblers (Sylvia borin), a different effect was observed: the warblers changed the direction of their flight and flew to the pole (north).

The authors suggest that such differences may be due to the fact that different species use different orientation strategies. So, in addition to the magnetic field, they can evaluate the location of stars or the change in the length of daylight. Probably because of this, in the absence of additional signals, marsh warblers and gray flycatchers could not "reorient" after the conditional crossing of the magnetic equator.

The Grey Flycatcher

Photo: Nikita Chernetsov

— We have previously shown that birds can master the stellar compass not only during previous migrations, but also immediately before and during the first flight. They can watch the starry sky, stopping along the way. For example, marsh warblers make a long stop in Kenya, where they have the opportunity to explore new starry "maps". Our new study confirms that bird navigation is not just following a strict program, but a complex process combining innate mechanisms and adaptation to external conditions," Nikita Chernetsov, project manager and head of the Ornithology laboratory at the Zoological Institute of the Russian Academy of Sciences, told Izvestia.

How bird navigation data is used in drone development

In the future, scientists plan to conduct experiments with adult gray flycatchers that have already crossed the magnetic equator and were in a horizontal magnetic field. Thanks to this, the researchers want to understand whether experienced birds will be able to react to the horizontal field as a signal to start orienting themselves not to the magnetic equator, but to the magnetic pole in order to continue flying south.

"Understanding these mechanisms not only expands our knowledge of nature, but also opens up new opportunities for creating bio—inspired technologies, for example, in robotics and autonomous movement systems," Nikita Chernetsov emphasized.

Photo: TASS/EPA/ATTILA KOVACS

The data itself is not new — the ability of birds to navigate along magnetic field lines and daylight hours has been known for a long time, but the phenomenon itself has not been sufficiently studied, Irina Golovacheva, Deputy director of the Institute of Ecology of the RUDN University, commented on the study to Izvestia. Man has always learned from nature, and most inventions are "spied on" by nature.

— Currently, human orientation takes place via GPS using the Internet. Navigation by electromagnetic fields will allow you to plot routes where there are problems with GPS. And also, perhaps, based on this mechanism, it will be possible to create portable autonomous location detection equipment," she said.

A photo of magnetic rings in which scientists changed the magnetic field

Photo: Nikita Chernetsov

In general, these factors are already embedded in inertial and azimuthal navigation systems for drones, said Pavel Kamnev, Commercial Director of Laboratory of the Future, market expert at Aeronet Research Institute.

— The "bird" orientation in the sky was first developed during the creation of the first unmanned systems in the 1920s, and in the Soviet Union in the 1930s. The bird understands that it needs to migrate by changing the length of daylight. Next, she uses landscape orientation, orientation according to the Earth's magnetic field, orientation according to the sun and stars, that is, they have a certain internal timer and compass," the specialist said.

Orientation cages and a video camera that captures the behavior of birds

Photo: Nikita Chernetsov

The data obtained is very interesting, but the accuracy is unclear. For drones, it should be a submeter, and preferably a centimeter, Nikolai Ryashin, CEO of Rusdronoport, an expert on the Aeronet NTI market, told Izvestia.

— It is unlikely that birds in their built-in "beacons" have an accuracy of positioning and geography up to 50 cm. Most likely, we are talking about kilometers, and maybe even hundreds of kilometers. Birds most likely fly to some geographical area, although they travel long distances. Drones need more accurate data," he said.

Characterized by intelligence and cleverness: the symbolic flight of the raven through the ages

It's a marvelous but not fat bird

The results of the study, supported by a grant from the Russian Science Foundation (RSF), have been published in the journals Frontiers in Physiology and Journal of Experimental Biology.