Many animals would tell us fascinating stories about their behaviors and marvelous abilities if only we could understand their language. As a result of years of research, many outstanding features of different animals have been discovered by scientists and these findings have formed the basis for numerous inventions. The Pacific golden plover (or the kolea, as it is called in Hawaii) is one such animal that is created with amazing abilities, like conserving huge amounts of energy with incredible techniques.

The Pacific golden plover is a migratory bird. The mother and father birds leave their nests in Alaska when their chicks are only a few months old, and return to Hawaii where they are originally from. Chicks by then have not yet learned how to fly [1]. After spending the summer in Northwest Alaska [2], when the winter comes chicks take off en route to the Hawaiian island where their parents are and where they have never been before. Considering that the distance is 4500 km (~2800 miles), this journey seems almost impossible for such a small bird, which, unlike many birds capable of trans-oceanic migrations, cannot swim, soar, or glide and weighs approximately 130 grams (~4.6 ounces).

Flying over the Pacific Ocean all the way from Alaska, the most extreme point of North America, to the island of Hawaii, the golden plover does not have a chance to land even for a short time to gather energy. The bird absolutely cannot fall under 130 grams either, because under this weight it would not have the energy needed for the remaining distance, which would be the end for the bird. To complicate matters even more, the Pacific golden plover loses 0.6% of its body weight every hour that it flies non-stop. There are two significant problems in this long journey; the fact that it cannot gain energy during its flight, and the problem of navigation. Not knowing which direction to fly in the vast ocean, or flying in the wrong direction for a short time, means an inevitable death for the bird.

The information we have obtained about this bird’s amazing ability to conserve energy journey is amazing. The flight time is 88 hours, or three days and four nights. For comparison, a modern Airbus A380 or Boeing 777-200LR can only fly about 18 hours without refueling [3]. During the flight, the Pacific golden plover flaps its wings 250,000 times, setting another record. “Imagine” says Dr. Oscar Wally Johnson from Montana State University “that flight you made from L.A. to Honolulu – only without the plane” [4].

Observations that have been made during the bird’s flight help us to understand how it overcomes these challenges [5]. The birds prepare for their journey by eating a lot and gaining a lot of weight in a short time. An average golden plover weighs roughly 130 grams and gains 70 grams of more weight, more than half of its body weight, during this intense eating period. Imagine a person that weighs 176 pounds (80 kg) gaining 100 pounds (45 kg) more to become 125 kg (275 pounds) in two weeks. The bird would normally lose 0.6% of its weight every hour it flies without a rest, and at the end of 88 hours it would remain only 117.8 g. As mentioned above, should the bird fall below its regular weight of 130 grams, it would be too exhausted to complete the journey. As soon as the bird runs out of energy, it would still have more than 497 miles (800 km) left before it reaches its destination. So, how is this problem solved?

If we want to save money on long car drives, then we set our cruise control to 110 km/h (~68 m/h) and drive at a constant speed. The bird does just that, and flies the whole distance at a constant and optimal speed of 51 km/h (~ 32 m/h) [6]. Flying slower than this speed would increase the amount of “fuel” that would be consumed, and flying faster would increase the energy consumption due to air resistance. Pacific golden plovers also fly in a “V” formation where the foremost birds flap their wings thus generating airflow that allows the birds in the rear of the formation to not have to use their wings in order to conserve energy [7]. Birds that are tired in front of the formation change their position with the ones who have had some rest at the back. Thus, they save about 23% of their energy and reach their destination of Hawaii while being slightly overweight. This excess weight is not stored in vain; it is estimated that more energy will be consumed in the case of bad weather conditions. During their flight, it is possible that the air could be foggy, cloudy, very sunny, or even rainy and windy, in which case their energy consumption can increase.

How does this bird determine the direction it should go? Imagine that this bird flies in absolute darkness for three nights without getting lost despite the fact that even a small deviation from their path could cause a huge deviation in the long run and cost the bird a fortune. They keep their flight formation and reach their destination despite all kinds of difficult conditions, including rain at night. With the help of a compass miraculously placed in the brains and eyes of these birds [8], they follow the magnetic field lines of the earth at a certain angle, adjust their position and follow their paths without facing any surprises [9]. Some scientists believe that the magnetic field map of the world is recorded in the eyes of migratory birds.

Migratory birds can also use the sun to correct their flight path. This difficult journey is successfully completed with the immigration program embedded into their genetic code by the Almighty Creator.

With their excellent energy saving and navigation features, the Pacific golden plover, a migratory bird species that has been doing this long-distance journey for thousands of years, provides us with very important lessons that can lead us to deep contemplation.

 “Have they never considered the birds above them, flying in lines with wings they spread out and fold in? Nothing holds them up except the All-Merciful. He indeed sees everything very well.” Mulk 67:19

References

1. If animals could talk-Wenn Tiere reden könnten Werder Gitt, K.-H.Vanheiden
2. https://academic.oup.com/auk/article-abstract/100/3/607/5185692
3. https://de.statista.com/statistik/daten/studie/232416/umfrage/reichweite-der-airbus-modelle/
4. https://hanahou.com/7.6/flight-of-the-navigators
5. https://www.nabu.de/tiere-und-pflanzen/aktionen-und-projekte/birdwatch/index.html
6. Peter F. Major, Lawrence M. Dill: The three-dimensional structure of airborne bird flocks. In: Behavioral Ecology and Sociobiology Band 4, Nr. 2, 1978, S. 111–122.
7. Cutts, J. Speakman: Energy savings in formation flight of pink-footed geese. In: J. theor. Biol. Band 189, Nr. 1, 1994, S. 251–261.
8. https://www.weltderphysik.de/thema/hinter-den-dingen/wie-finden-zugvoegel-den-weg/
9. https://www.spektrum.de/frage/orientierung-wie-finden-zugvoegel-ihren-weg/1425607

Animals such as butterflies, turtles, and birds are given the ability to perceive the Earth’s magnetic field and navigate themselves accordingly. Migratory species also benefit from the sun, stars, and even scents in nature as they from one place to another.

Magnetic fields and poles

Modern studies have focused on how animals perceive the Earth’s magnetic field and act accordingly. We need to look closer at the Earth’s “magnetic polar points” to understand how magnetic fields work exactly.

It is important not to confuse geographic and magnetic poles. There is a layer called the “inner core” in the center of our Earth where all substances are in a fluid state, similar to those seen in volcanic eruptions. Volatile and molten elements such as nickel and iron form a magnetic electric field above the Earth. This is also the force that is responsible for causing our compasses to point north. At the center, the Earth’s magnetic field changes due to these fluid substances. That is, our compass does not always show the “true north,” i.e. the exact geographical north.

As of the last decade, the Earth’s magnetic pole has kept moving at a rate of about 55 km per year. The magnetic north pole, found in Canada in 1831, has now shifted 2300 km and approached Siberia. Scientists say that about 780 thousand years ago, today’s southern and northern magnetic poles were exactly the opposite. Although the magnetic poles shift, the Earth’s magnetic field continues to function properly. This is imperative for protecting all life on Earth, as a balanced magnetic field protects our planet from the magnetic effects of solar flares and solar winds.

Effects of polar shift

A new magnetic map of our planet is released every five years due to the fact that our magnetic poles are constantly shifting. This does not affect most people on a daily basis, however it does present a challenge for people and vehicles that rely on a compass. Due to the shift, a difference called “magnetic declination angle” occurs between the magnetic north pole and the geographic north pole. This angle varies according to the location. For example, in Canada the magnetic deflection angle is 13 degrees whereas in Brazil it is 20 degrees. In order to determine their exact location, military and civilian aircraft and ships manually or automatically calculate their location based on the angle of deviation and navigate accordingly. Even if we are not aware, our mobile phones are automatically updated according to this calibration. In physics, the formula known as Lenz’s Law, or a tool called a gaussmeter, can be used to calculate the Earth’s magnetic field.

Cryptochromes

This complex and intricate system affects most animal life on Earth, including birds, insects, and fruit flies. So, if these magnetic poles keep changing how do animals find their way? Most creatures utilize cryptochromes, a type of flavoprotein that affects their body clock.

Cryptochrome (CRY) [1] is found to play a leading role in this regard. Cryptochrome-2, one of the two cryptochrome photoreceptors, has been proven to be instrumental in regulating the daily life rhythm of beings by fine-tuning their body clocks and assisting certain animals such as migratory birds, king butterflies, and fruit flies to navigate their migratory paths accurately.

Years of research conducted by Steven Reppert and his team at the University of Massachusett’s School of Medicine on fruit flies and butterflies revealed the function of cryptochrome-2.

According to the research published in Nature magazine in 2009 [2], Dr. Reppert and his team found that flies could not adjust themselves to a new magnetic field without any form of cryptochrome, but that they could regain their sensitivity to a magnetic field only after cryptochrome-2 production.

During the study, the genetic structure of fruit flies was examined and it was ensured that they produced cryptochrome-2.

Speaking to the BBC, Dr. Reppert emphasized that they developed a system to understand how the perception of the magnetic field works in fruit flies. They sought the answer to the question, if cryptochrome-2 was to be transferred from animals to flies, can these proteins act like magnetic sensors in other forms? They have found out that human beings were the most effective option among all vertebrates to yield cryptochrome for this purpose. Their experiment with butterflies yielded the same results. They observed that flies without cryptochromes did not show any signs of magnetic field detection only until their genetic structure was intervened to produce a human version of the molecule.

In another experiment carried out by scientists, a group of migratory birds had iron nuggets, some of which were magnetized to scramble the Earth’s magnetic field, attached to their feet. It was observed that the birds with magnetized nuggets lost their migration path and the birds with unmagnetized nuggets could navigate as easily as usual.

Of course, birds could not know these exact calculations that many people do not even know. Pathfinding skills are “programmed” into birds before they are born so that even if the magnetic field shifts this wonderful mechanism in animals always delivers them to the right location.

The loggerhead sea turtles

As soon as they hatch on the east coast of Florida, the loggerhead sea turtles, Caretta Carettas, swim into Sargasso Sea, migrate into the North Atlantic Circle, and then subsequently into the Atlantic Ocean. The turtles first swim to the northeast towards Europe, then to the south, and return to North America after spending 5-10 years in this hot and nutrient-rich migratory loop.

Dr. Kenneth Lohmann and his team at the University of North Carolina wanted to observe whether loggerhead sea turtles used regional magnetic fields to find their migration paths. They set up a mechanism in a large water tank that was installed with coils in order to form multiple magnetic fields. 79 newly hatched turtles were then clad in cloth vests with wires connected to a computerized monitoring system and left in the same tank. Juvenile turtles were subjected to magnetic fields equivalent to those that exist at critical points of the North Atlantic Cycle, such as in the north of Florida, off the coast of Portugal, and at the southern end of the cycle. As a result, it was observed that in every magnetic field simulated in the experiment, the turtles begin to swim in the opposite direction. For instance, when the magnetic field in the northeastern part of the loop was applied, the animals headed south. In a real ocean setting, this direction keeps them on the right track and prevents them from entering icy waters and dying of hypothermia.

How do animals do it?

There are several research works documenting that not only birds, but also bats, ants, foxes, deer, and even cows feel magnetic fields.

Animals generally migrate to find more suitable reproductive, feeding and living areas for themselves. It is amazing how they know which way to go as soon as they are born. How do they decide that a place they’ve never been to is most suitable for them? How did they learn those navigational skills?

It is amazing to observe this intricate and interlinked system between the Sun, the Earth, and all the living things in it: while the rays of the Sun are needed for life, the harmful ones among them need to be shielded away from the Earth with a magnetic field, a field which is detected by a protein in animals so they can travel to places to continue their lives.

Human cryptochrome

Cryptochrome proteins are also present in the human body [3]. Cryptochrome-2 is especially functional and is linked more to adjusting biological rhythm rather than perceiving the Earth’s magnetic field.

Dr. Aziz Sancar, Chemistry professor and Nobel Prize winner, observed in his experiments of circadian clocks [4] that the cryptochrome pigment located in the eye, skin, and part of the brain regulated the circadian rhythm of mammals.

Currently, many theories are proposed and experiments are conducted on discovering the extent that human beings can perceive the Earth’s magnetic field.

Meanwhile, the wisdom behind the constant shift in the Earth’s magnetic pole awaits to be revealed.

Notes

1. https://en.wikipedia.org/wiki/Cryptochrome
2. Buchen, Lizzie. “Butterflies’ Migrational Timekeeper Found.” Nature, September 24, 2009.
3. Discovered between 1996 and 1998 in humans by Aziz Sancar and his colleagues, cryptochrome is one of the four genes that set the circadian clock in mice. This protein is also a member of a family of proteins including photolyase, DNA’s repair enzyme, on which Prof. Aziz Sancar has worked throughout his scientific career.
4. Rhythmic behavior and physiological changes that have a 24-hour cycle and regulate the day and night cycles of living beings. 

Further reading

Attenborough, David. 1998. The Life of Birds, Princeton University Press Princeton, New Jersey.