Bird Migration and Global Environmental Conservation

2022/02/16

Before discussing bird migration, I would like to talk about how the nature and ecosystem of a single region are composed of three major groups. These are plants, which produce organic matter as nutrients; animals, which take in those plants directly or indirectly as food; and fungi and bacteria, which act as decomposers by breaking down the remains of plants and animals in the soil and returning them to inorganic matter.

Plants use solar energy to perform photosynthesis, creating nutrients and organic matter from water and carbon dioxide. Without photosynthesis by plants, animals could not survive. In the sense that they produce organic matter, plants can be considered "producers." Animals that use them directly or indirectly as food can be considered "consumers." When their remains are decomposed in the soil by fungi and bacteria, returning organic matter to inorganic matter, some of those inorganic substances become nutrients that are absorbed through plant roots and used for plant growth and reproduction.

Regional nature is sustained by the successful circulation of these plants as producers, animals as consumers, and fungi/bacteria as decomposers. To reiterate, without the existence of plants as the source of life for living things—producing organic matter through photosynthesis—animals could not survive. They are indispensable to life and livelihood.

We humans, as a type of animal consumer, are also positioned somewhere within this natural system. We live and sustain our livelihoods within this mechanism of nature. It is a truly excellent system created by nature, but it is also one that relies on delicate relationships between various organisms.

The nature and ecosystem of a single region do not exist in isolation. They are connected in various ways to the nature of distant countries and regions. Through this, the nature and ecosystems of both the region and the entire planet function.

Humans live and sustain life within the natural systems of both the region and the entire globe, but in recent years, we have been destroying and altering nature in various ways. As a result, the face of nature has changed significantly, and this is reflecting back on the human world as a negative impact. As you are aware, we see effects such as increasingly large typhoons, tornadoes, and global warming. We need to properly understand the makeup of the nature that surrounds us and the world of the living things we live alongside. Furthermore, we need to know and understand how our activities affect and change nature.

Migratory birds play a very large role in connecting the nature of distant countries and regions. At the same time, migratory birds connect people in distant lands and act as carriers of "emotional exchange." By understanding the status of migratory birds that move on a global scale, we can deepen our understanding of the connections between nature, living things, and people.

In the following, I will first introduce the actual state of bird migration in detail, then consider the causes of the global decline in migratory birds, and finally conclude with a talk on the role of migratory birds in connecting people.

Many birds travel long distances between breeding grounds and wintering grounds every autumn and spring. This seasonal round-trip movement is called "migration." In the process of migration, birds obtain water and food from various natural environments, while simultaneously connecting the nature of distant countries and regions, contributing to its healthy maintenance.

On the other hand, birds encounter various environmental problems during migration, and their numbers are rapidly decreasing. The Amur River, which flows through the Amur region of Russia, is a great river separating Russia and China. Oriental Storks breed in the basin, but the number of breeding pairs is decreasing year by year.

Hearing this, you might think that extensive environmental destruction is taking place in the Amur region, but that is not the case. The breeding grounds are untrodden lands where wonderful nature spreads out. We researchers fly over the area in helicopters from morning to evening, skimming the ground to investigate changes in the natural environment and the condition of the birds.

Despite breeding in such a wonderful natural environment, the population of Oriental Storks is rapidly declining. It is predicted that there are likely major problems at the stopover sites along the migration route or in the wintering grounds.

Summer birds that visit Japan are also decreasing. These are birds such as the Grey Nightjar, Ruddy Kingfisher, Ashy Minivet, Ruddy-breasted Crake, Brown Hawk-Owl, and Japanese Paradise Flycatcher, which migrate from the south in spring to breed in Japan and migrate south in autumn. These may be unfamiliar names, but the number of confirmed habitats is decreasing year by year.

The Japanese Paradise Flycatcher is written as "Three-Light Bird" (Sankoucho) because it sings "Tsuki, Hi, Hoshi, Hoi-hoi-hoi." Moon (Tsuki), Sun (Hi), and Star (Hoshi). It gets its name from incorporating these three lights into its song.

In the 1970s, the Japanese Paradise Flycatcher bred quite commonly everywhere in Japan's satoyama and hilly rural areas, including Tokyo, Kanagawa, and Saitama. Their characteristic song would often reach our ears in May and June. At the time, I never imagined that the Japanese Paradise Flycatcher would eventually disappear.

However, entering the 1980s, they began to decrease rapidly in various places. According to records by Hiroshi Uchida, who lives in Higashimatsuyama City, Saitama Prefecture, the population of Japanese Paradise Flycatchers plummeted after the 80s and eventually reached zero. I will explain later what exactly happened.

There is a bird called the Yellow-breasted Bunting, a relative of the bunting characterized by its yellowish color. In the 1970s, it was one of the most numerous birds in the grasslands of Hokkaido. However, it also decreased rapidly thereafter, and now only a few breeding pairs can be confirmed in areas like the Sarobetsu Wetland in the north.

This declining trend of the Yellow-breasted Bunting is the same not only in Hokkaido but also on the continent. In Europe, the population has decreased to less than 20% of its peak, and it has disappeared in some countries.

The same applies to the Grey-faced Buzzard, a member of the hawk family. The Grey-faced Buzzard is a hawk that feeds on amphibians and reptiles, primarily snakes and frogs. The population of Grey-faced Buzzards is counted every year mainly by school students on Miyako Island (strictly speaking, Irabu Island) in Okinawa Prefecture during their migration. Although the results fluctuate year by year, the population is clearly decreasing rapidly.

To conserve animals that move on a global scale like migratory birds, it is necessary to accurately investigate the entire migration route and clarify the locations of wintering grounds, stopover sites, and breeding grounds, as well as the conservation issues in those areas.

Migratory birds travel hundreds, thousands, and in some cases, over ten thousand kilometers. Since we cannot follow the birds, we observe the state of migration at specific locations. Until the early 1990s, we could only use our imagination to wonder where they were going while watching them, but since then, with the development of science and technology, we have become able to track them using satellites.

This is a mechanism we call "satellite tracking." A small transmitter is attached to the bird's back, neck, or the base of its tail. Radio waves are emitted from the transmitter, reaching a system called the Argos system on a satellite, and the data is transferred to a ground station to determine the time, latitude, and longitude. Researchers then obtain this numerical information via the internet. Using this mechanism, we can track the position and movement of the target creature no matter where or how it moves on Earth. Once the transmitter is attached to the subject, the rest of the work of following the migration can be done on a computer—it is a truly wonderful system.

This system was born in the early 1990s. Entering the 2010s, even smaller devices called "geolocators" were developed. A geolocator is about the size of a fingertip, weighing less than a gram—the smallest ones are about 0.3 grams. Since a one-yen coin weighs one gram, these are about a third of that size and can be attached even to small birds. Geolocators use light sensors to continuously record the times of sunrise and sunset. Since sunrise and sunset times vary by region, we can investigate the transition of latitude and longitude of the movement points based on that data.

Satellite tracking has an error of about one kilometer in position measurement. However, that is sufficient for tracking the migration of birds traveling thousands of kilometers. Geolocators have poorer accuracy, with errors of over 100 kilometers, or in some cases, a shift of about 200 kilometers. But to understand the migration of small birds about which nothing is known, even that level of error is sufficient for the time being. Since we can roughly know where and how they fly, they are being used more frequently among researchers.

In Japan, there are birds called Whooper Swans and Tundra Swans, and we track both. Today I will introduce the Whooper Swan. There are over 500 lakes in Japan visited by swans, making them very familiar, but until we started satellite tracking, we had no idea where they came from or where they went.

As a result of satellite tracking, we found that the spring migration moves north from Izu-numa in Miyagi Prefecture in March and April. After staying in eastern or central Hokkaido for a while, they move north through Sakhalin and stay near the mouth of the Amur River for ten days to a month. Then, they cross the Sea of Okhotsk back to the continent, continue north, and breed in the areas of Russia's great rivers such as the Kolyma and Indigirka rivers. In autumn, they perform a simple north-south migration, returning almost exactly along the spring migration route.

For the White-throated Needletail, known as the fastest bird in level flight, we use small GPS (Global Positioning System) devices along with geolocators for accurate measurement. It is known that the White-throated Needletail flies at incredible speeds of roughly 120 to 150 kilometers per hour even in normal horizontal flight.

We tracked three individuals equipped with geolocators to see where and how the White-throated Needletail passes in autumn and what kind of migration it performs in spring. Although there are some individual differences, in the year-round migration from August to the following May, they depart from Obihiro, which is their breeding ground, go to the continent, pass through the Philippine Sea and Papua New Guinea, and "winter" (actually summer, as it is the Southern Hemisphere) around southeastern Australia. Later, in spring, they go toward Indonesia and move north, returning to Obihiro via the Nansei Islands. Roughly speaking, we found that they migrate in a figure-eight pattern across the Pacific Ocean throughout the year.

In Izumi, Kyushu, White-naped Cranes and Hooded Cranes migrate from the continent in numbers not of a thousand, but tens of thousands. Recently, about 16,000 birds arrive every year. A few years ago, bird flu occurred, and there were concerns about the spread of infection, but perhaps because antibodies exist within the cranes, the situation has not developed into the feared scenario so far. While cranes are subjects of conservation, they also carry the risk of spreading infectious diseases. Japan is essentially looking after 80% of the world's White-naped and Hooded Cranes during the winter, and for their conservation and management, plans to disperse the cranes are being discussed.

Tracking the spring migration of White-naped Cranes, they depart Izumi in February or March and move along the Kujukushima Islands at the western edge of Kyushu, which is a very beautiful scenic area. Interestingly, from there, the White-naped Cranes fly toward the "DMZ (Demilitarized Zone)" between South and North Korea. They stay there for a week to a month and then split into two routes for migration. One goes north along the east coast of North Korea to the Sanjiang Plain in northeastern China. The Sanjiang Plain is a vast wetland surrounded by three rivers: the Amur, Ussuri, and Songhua. The other route goes north along the west side of the Korean Peninsula to an area called Zhalong near Harbin and Qiqihar in northeastern China.

In this tracking, we investigated where and for how long nine White-naped Cranes stayed during the migration process (Figure 1). According to the results, they use four locations as major stopover sites. Panmunjom, located along the DMZ separating North and South Korea; Cheorwon, also along the DMZ; Kumiya, along the east coast of North Korea; and Lake Khanka, along the border between Russia and China. In particular, many individuals stay for long periods in Cheorwon and Panmunjom along the DMZ.

The DMZ is four kilometers wide. On the south side in South Korea, there is a buffer zone called the "CCZ (Civilian Control Zone)." In the CCZ, some farming is permitted and it is open to tourism, but a restriction line is drawn at the boundary with the DMZ, and entry inside is completely prohibited. This means the cranes' stay points are within an area where people cannot enter. North Korea, on the north side of the DMZ, does not have a CCZ, so it is an area used by humans right up to the edge; however, we found that the White-naped Cranes do not stay on that side.

Looking at the example of Red-crowned Cranes, those in Hokkaido do not migrate long distances, but Red-crowned Cranes that breed along the Amur River on the China-Russia border stay temporarily in Anbyon, North Korea, before moving south to winter in the DMZ. Hot springs bubble up in the DMZ, and the rivers are non-freezing. Meanwhile, the CCZ to the south is used as a foraging site. Therefore, Red-crowned Cranes spend their winter life foraging in the CCZ during the day and soaking their feet in the hot springs in the DMZ at night. Border zones have become important arrival sites for migratory birds, and the DMZ, where entry is prohibited and economic development does not occur, has become a paradise for the birds.

For research purposes, I have entered the CCZ many times, but there are strict checkpoints at the entrance. The area sandwiched between South and North Korea beyond those checkpoints has become a safe haven for the cranes. Even now, North and South Korean soldiers face off with automatic rifles, and in the middle of that, the cranes live peacefully. It is quite ironic, or rather, a noteworthy phenomenon. Countless landmines from the Korean War era are buried in the DMZ; it seems they do not explode if a crane steps on them, but they will explode if a person does.

Migratory birds have no borders. People cannot cross the DMZ to come and go, but the cranes move back and forth freely.

To add a little more, this situation has changed recently, and cranes are starting to concentrate in Cheorwon. This is because, like Izumi in Kyushu, artificial feeding has become active in Cheorwon.

Figure 2 shows the results of tracking the autumn migration of Grey-faced Buzzards breeding in northern Kyushu. On a single map, you can see them departing the southern tip of Kyushu and moving south from the Nansei Islands to the Philippines. Until we saw this, we thought all Japanese Grey-faced Buzzards moved south via Taiwan. However, we found that from mid-October, they move south along the Nansei Islands and go as far as Luzon Island in the Philippines to winter without stopping in Taiwan.

We found that birds that continue moving until the end enter Luzon Island on November 5, continue moving south thereafter, and finally finish their migration south of Mindanao Island in early January.

There is a bird called the Oriental Honey-buzzard, a relative of the hawk that feeds primarily on bees. Parent birds catch bee pupae and larvae to feed their chicks or eat themselves. Since these food resources disappear from Japan's temperate regions during autumn and winter, they go south. Unlike the Grey-faced Buzzard, even though they are both raptors, the Oriental Honey-buzzard migrates very long distances via the continent. This is likely because many bee resources exist on the continent. Since Oriental Honey-buzzards eat many bees, such as giant honeybees, at stopover and wintering sites, they may know where bees gather. They might also be visiting apiaries. It can also be inferred that the reason they do not move south through the Nansei Islands like the Grey-faced Buzzard is that bee resources in that region are poor.

I have introduced various bird migrations so far, but the migration of the Oriental Honey-buzzard is the highlight. Oriental Honey-buzzards breeding in Aomori and Yamagata cross 700 kilometers of the East China Sea, where there are no islands, during their autumn migration. Once they enter the continent, they move south through areas slightly inland from the east coast of China. While tracking them, I watched the computer screen every day with a racing heart, wondering how far they would go. The Oriental Honey-buzzards continue south, entering the Malay Peninsula from the Indochinese Peninsula. From there, they continue further south. Eventually, they enter Sumatra via Singapore. Here, one group moves to Borneo and goes further north to around Palawan Island in the Philippines. We found that another group heads east from Sumatra, passing through Java and the Lesser Sunda Islands to around Timor Island. They fly along fixed routes as if there were roads in the sky (Figure 3).

In February, the spring migration toward Japan begins. Up to a certain point, they return almost exactly along the autumn migration route in reverse. Both the group that wintered in Borneo and the group that wintered in Timor return to Sumatra. Interestingly, unlike in autumn, in spring every single individual stays for a long period somewhere in Southeast Asia or southern China.

After spending a week to a month at these stopover sites, they continue north again. In the autumn migration, they moved south near the east coast of China, but in spring, they pass through much more inland areas. From this appearance, it seems they might not return to Japan, but they return properly. When they move north to the north of the Korean Peninsula, they actually move south down the peninsula from there, enter Kyushu, and head toward their breeding grounds in the east. Some birds are late, but even so, they all take similar routes. Tracking many individuals yielded similar results.

There are several noteworthy points. One is that Oriental Honey-buzzards visit every country in East Asia one by one through their spring and autumn migrations. It is somewhat unbelievable. Another surprise is that the destination they return to is accurately determined for many individuals as a specific location in Yamagata or Aomori prefectures. In human terms, it is determined with the precision of a specific street address and house number.

Over 10,000 kilometers one way, over 20,000 kilometers round trip in spring and autumn, and the migration routes for spring and autumn are significantly different. Despite this, returning accurately to a specific house number is very difficult for us humans to understand. For example, if I were told to "walk back to my home in Yokohama" from here, I probably wouldn't be able to return properly (laughs).

Without maps, compasses, or of course GPS, birds follow a route with a total travel distance of over 20,000 kilometers that differs between spring and autumn, and return to a specific region in Japan on their own. It is amazing.

Why do Oriental Honey-buzzards have different migration routes in autumn and spring? The key to this difference is the East China Sea. In autumn, a stable tailwind from the east blows across the East China Sea. Oriental Honey-buzzards use this tailwind to cross 700 kilometers of ocean. May, when the spring migration occurs, could be called early summer, but the climate of the East China Sea and surrounding waters is unstable. In such conditions, crossing the sea from west to east is very dangerous. It is safer to cross less than 200 kilometers of sea from the Korean Peninsula via Tsushima.

Figure 4 is something often seen on weather maps recently; the tips of the arrows indicate wind direction, and the length of the arrows indicates wind strength. The small ○ and □ in the figure show the positions of a single Oriental Honey-buzzard during movement. The gray parts are low-pressure systems, or large masses of clouds. In autumn, a tailwind toward the south blows in the East China Sea. Oriental Honey-buzzards cross the 700-kilometer sea while utilizing this tailwind. When a low-pressure system develops, the wind direction may reverse, forcing them to stay, so they temporarily stop at Fukue Island, an island at the western edge of Japan, but when the tailwind returns, they all cross together.

In spring, wind conditions over the East China Sea become unstable, and crossing there to enter Kyushu is dangerous, so they enter Kyushu via the Korean Peninsula. It can be said that birds migrate according to favorable meteorological conditions, especially wind conditions such as wind strength and direction.

When exploring the causes of the decline in migratory birds, environmental modification is the most important factor. Environmental modification of forests, wetlands, and coastal areas that serve as breeding grounds and stopover sites is occurring everywhere. For example, the Daisetsuzan mountain range in Hokkaido and the Sanjiang Plain in Heilongjiang Province, China, where cranes migrate. The Yatsu Tidal Flat on the border of Tokyo and Chiba is already polluted, and the Tokyo Bay coastal area has been surrounded by buildings. Such massive environmental modifications are being carried out in various places, and the loss of places for birds to go is one major cause of the decline.

Even if it is not large-scale environmental destruction, environmental modification is also taking place in satoyama areas. Deforestation for residential land development, changes in paddy field structures due to modernization, and the abandonment of rice cultivation and paddy fields due to an aging population are leading to population declines through the loss of habitats and food.

For example, traditional rice paddies had waterways alongside them, and rice cultivation was carried out while moving water in and out from there. There was an exchange of water between the waterways and the paddies, allowing aquatic creatures to sustain their lives. However, with recent land consolidation and agricultural structure reforms, when waterways are made into three-sided concrete revetments, frogs and other creatures become unable to get out of the waterways.

Problems are also occurring in wintering grounds and stopover sites. I mentioned earlier that the Japanese Paradise Flycatcher is rapidly decreasing. In Sumatra, which is an important wintering ground for the Japanese Paradise Flycatcher, tropical rainforests are being cleared one after another. There are also examples where places that were once peaceful rural landscapes have changed into large-scale plantations for oil palms and other crops.

There is also the issue of wind power generation. Wind power is certainly attracting attention as clean energy and is important, but if wind turbines are constructed carelessly, it creates a problem where many birds collide with them. Numerous wind turbines stand at the mouth of the Yellow River in China, and many migratory birds, including sandpipers and plovers, may be affected.

Then there is the problem of poaching. It is known that at least 3,000 to 5,000 Grey-faced Buzzards are poached every year on Luzon Island in the Philippines, where they winter. As a result of various activities for conservation developed through cooperation between protection groups, researchers, and local governments, poaching has been successfully eradicated in this location. However, sufficient measures have not yet been taken in other regions. In Hong Kong, because a significant number of Yellow-breasted Buntings migrate there, they have become targets for poaching, and many individuals are actually being roasted.

I will also briefly introduce the effects of global warming. It is known that the breeding seasons of small birds such as the Red-cheeked Starling are becoming earlier year by year. The fact that breeding and arrival times are becoming earlier is not the only problem. Due to global warming, a phenomenon is occurring where the timing of the appearance and behavior of organisms is shifting and becoming earlier at different rates for each species or taxonomic group in the same region.

Specifically, the response of plants to global warming is slower compared to animals. Results from an analysis of over 200 species of flora and fauna in the Northern Hemisphere show that the advancement of butterfly appearance times and migratory bird arrival times is progressing three times faster than the advancement of plant flowering times. What this brings about is a shift or disruption (mismatch) in the interactions between organisms.

In other words, the breeding season of the Red-cheeked Starling becomes earlier, and the flowering season of cherry blossoms also becomes earlier. However, while the birds have become more than two weeks earlier over the same 28-year period, cherry blossoms have only become 8.5 days earlier. Furthermore, no such prominent trend is seen in the Cabbage White butterfly. Consequently, since the speed of change differs among the three, a mismatch occurs. For example, the proportion of cherry fruits included in the food of Red-cheeked Starling chicks is decreasing year by year and has almost disappeared recently. This situation may make it difficult for Red-cheeked Starlings to breed in the near future.

There is research that uses computer simulations to represent the future migration routes of the Oriental Honey-buzzard (Figure 5). The IPCC (Intergovernmental Panel on Climate Change) has drawn several different scenarios for the progress of global warming. Among them, the RCP8.5 scenario is considered to have a relatively large impact. Under this scenario, it is predicted that the suitable migration sites shown in dark colors in the figure will disappear by the end of this century. What the Oriental Honey-buzzard will do at that time is not yet known.

What is important is that multiple threats are occurring simultaneously for the same region, the same birds, and nature. For example, it is not uncommon for deforestation, collisions with wind turbines, chemical pollution, or global warming to strike at the same time. In the case of migratory birds, multiple problems overlap along the migration route. Even if there are problems like habitat destruction, chemical pollution, and collisions with wind turbines in Japan alone, they are exposed to similar or different threats at every destination they migrate to. Even if measures are taken in only one country or region, if problems continue in other regions, migratory birds will decrease.

I believe you have understood well from the talk so far that "birds have no borders." Birds migrate across many countries without visas or passports. Migratory birds connect the nature of distant countries and regions, but at the same time, they also connect people.

In various parts of the world, exchange between people through migratory birds and various international cooperation for conservation are taking place. There are people watching the same flocks of birds and the same flocks of hawks in various regions along the migration route. For example, at Shirakaba Pass in Nagano Prefecture, or Irago Cape in Aichi Prefecture, Taiping in Malaysia, Chumphon in Thailand, and Tanjung Tuan in Malaysia.

Many of these people are not bird researchers. They are general citizens. Such people enjoy watching bird migration on an autumn day. Thousands of people gather to experience the sense of the season and spend time together.

Regarding conservation, heated discussions are being exchanged in various places at home and abroad. International conferences for conservation are held at Irago Cape in Aichi Prefecture, Taiping in Malaysia, and Bali. There are migratory bird protection treaties between several countries, and various matters are discussed between governments and also by private organizations.

After these conferences, exchange between participants continues. Social gatherings are held among young people from NPOs, where everyone spends time with good smiles after the formal meetings, discussing various things about conservation and deepening friendships (Figure 6).

At Keio University Shonan Fujisawa Campus (SFC), we also developed an activity called the "Bird Migration Satellite Tracking Public Project" from the autumn of 2012 to the summer of 2013. I think you all found the state of the Oriental Honey-buzzard's migration interesting, and we launched a project to make it public, thinking it would be a waste to keep it only among researchers (Figure 7).

  Figure 7 Keio University Bird Migration Satellite Tracking Public Project

In this project, we satellite-tracked four Oriental Honey-buzzards. We gave names to the four birds and made it possible to provide live updates, such as where bird A is going now or where bird B is flying, and made it public in real-time. The state of migration was not only shown on maps, but the information was also sent out in Japanese, English, Chinese, Korean, and Indonesian, and we exchanged opinions with participants.

There was access from all over the world, centered on East Asia, and an estimated total of about 100,000 people participated. Not only from Asia, but staff from large nature conservation organizations in the UK also joined the information exchange. Truly, people in distant countries and regions were connected through bird migration. It was a very meaningful project for me as well.

There is one striking example of migratory birds connecting people in distant regions. It is the "Bluebird of Happiness" that appears in Kimio Endo's "Arirang's Bluebird."

I will tell you the synopsis of this book. Pyong-oh, the youngest son of the famous North Korean ornithologist Won Hong-gu, had been observing birds with his father since he was a child. Pyong-oh was born in 1930. It was a difficult time under Japanese occupation, but the father and son spent happy days together.

However, when the Korean War eventually began, the family was torn apart. The parents were in the North, and Pyong-oh and his brothers were torn away to the South. The separated family was thereafter unable to meet or even contact each other by letter or telephone.

As time passed, Pyong-oh grew up to be an ornithologist in the South (South Korea). He became an assistant professor, and later a professor, at the prestigious private Kyung Hee University.

In May 1964, an envelope arrived in Japan from North Korea via Moscow. It was an envelope from the Institute of Biology of the Academy of Sciences of North Korea, stating that a Daurian Starling with a Japanese leg band had been found in Moranbong Park in Pyongyang. It was a request to tell them where it had been released, as it was wearing a Japanese leg band. The leg band was printed with a number and "Ministry of Agriculture and Forestry JAPAN."

As a result of the investigation, it was found that the leg band had been attached in Seoul. The person who attached the leg band was Mr. Won Pyong-oh, the son. And the person who inquired from North Korea was Won Hong-gu, who was serving as the Director of the Institute of Biology of the Academy of Sciences. He was Pyong-oh's father.

Through the leg band of the Daurian Starling, Mr. Hong-gu learned that his child, whom he had never forgotten for a moment, had grown up to be an ornithologist. Pyong-oh also learned that his father, for whose safety he had been concerned every day, was healthy and continuing his bird research. The leg band attached to the bird was something that both the father and son, who could not meet, had touched.

This was a truly heart-stirring event. The Korean War has still not ended. In the Demilitarized Zone separating North and South Korea, birds such as cranes and Oriental Honey-buzzards cross that boundary lightly as they come and go. Birds truly have no borders.

The Daurian Starling that connected the father and son could be said to have been a "bluebird that brings happiness," however modest it may have been. This event became a big topic at the time in South Korea, North Korea, China, Russia, Japan, and the United States. Commemorative stamps were issued in North Korea. The stamps depict the Daurian Starling, Mr. Won Hong-gu, and the leg band plate (Figure 8). It was also made into a movie.

However, due to the ongoing division of North and South, the opportunity for the father and son to meet directly never came, and Mr. Won Hong-gu passed away in 1970, and Mr. Won Pyong-oh passed away in 2020.

The message this Daurian Starling conveys to us, and what we should take from it, is not just that birds connect people. I believe it is that war makes no one happy.

Nature in different countries and regions is connected in various ways through bird migration. It can be said that the nature or ecosystems of various places constitute a mesh-like network through migratory birds.

The destruction of nature in one region leads to the alteration of nature in distant countries and regions through the decline of migratory birds. The destruction of tropical rainforests in Southeast Asia leads to the alteration of nature in Japan's satoyama and beech forests through the decline of migratory birds that winter there and breed in Japan. The destruction of tidal flats in Japan may lead to the alteration of nature in Southeast Asian tidal flats or the Russian tundra through the decline of sandpipers and plovers that rest and forage there.

Clarifying the specific connections of habitats is very important when considering the conservation of target species and the effects of global warming. Individual pieces of nature do not exist in isolation. In conserving the natural environment, it is necessary to have both a regional perspective and a global perspective.

Migratory birds have no borders. Through migration, birds also connect people in distant countries and regions. It can also be said that they connect the hearts of people. International cooperation is indispensable for the conservation of migratory birds and their habitats.

Over the past 30 years or so, I have received the cooperation of many researchers at home and abroad in advancing my research. The content I spoke about today is the result of joint research with such people. I received a lot of research funding from the government and the private sector. Without such cooperation and support, I would not have been able to continue my bird migration research until now. I would like to express my deep gratitude.

Thank you for your attention.

(This article is based on a lecture given at the 710th Mita Public Speaking Event held at the Mita Campus North Building Hall on December 14, 2021. Slides from the lecture have been selected and included as appropriate.)