Satellite tracking of migrating cranes and swans in eastern Asia

In order to satellite track migrating cranes and swans, the Wild Bird Society of Japan is cooperating with other research organizations such as the Nippon Telegraph and Telephone Corporation, the Yamashina Institute for Ornithology (Japan), the Central Research Laboratory of Game management and Nature Reserves (Russia), and the International Crane Foundation (U.S.A). The purpose of the research project is to describe the migration routes and crucial resting, breeding and wintering areas of endangered swans and cranes, and use that knowledge to conserve them and their habitats.

We first attached transmitters in April 1990 to four Whistling Swans, Cygnus columbianus, at Lake Kuccharo (45.1°N, 142.3°E) on Hokkaido, the northernmost main island of Japan (Higuchi et al. 1991 a, b). The transmitters, developed by the Nippon Telegraph and Telephone (NTT) Corporation, measured 112 mm x 35 mm x 19 mm, with a 187 mm antenna and mass of 83 g. Three of the four transmitters were attached to the backs of the swans. Two were set into leatherette harnesses with Teflon tubes, while one was glued straight onto the swan's back using epoxy resin adhesive. The fourth transmitter was attached to a collar band, fitted loosely around the neck.

The four swans migrated along similar courses, traveling north via Sakhalin Island, stopping over in the north of that island or around the mouth of the Amur River in Russia. They spent between several days and nearly a month there before going on. One swan was successfully tracked to its breeding ground at the mouth of the Kolyma River (68.6°N, 161.3°E) in Russia.

The batteries lasted for 30, 39, 42, and 46 days, considerably less than the anticipated life expectancy of about 60 days. The shorter duration may have been due to the long exposure to cold weather in northern areas.

In February 1991, we attached transmitters to five White-naped Cranes, Grus vipio, in Izumi (32.1°N, 130.2°E), southern Kyushu, the southernmost main island of Japan. The shape and size of the transmitters were similar to those used in the above Swan study. Three of the transmitters were attached to the backs of the cranes using leatherette harnesses with Teflon tubes, while the other two were glued directly onto the crane's back using epoxy resin adhesive. Harnessing was not totally successful, since the three transmitters harnessed with Teflon tubes fell off after a few days.

The two cranes with glued transmitters migrated north through Tsushima Island (34.3°N, 129.3°E) and the Korean Peninsula toward the Demilitarized Zone (38.2°N, 127.2°E) of the North Korean-South Korean border. They spent more than two weeks in the Demilitarized Zone (DMZ), but then the batteries became exhausted.

In September 1991, transmitters were attached to one Hooded Crane Grus monacha and two White-naped Cranes Grus vipio at the Daursky Nature Reserve (49.9°N, 115.6°E), close to the Russian-Mongolian border. The transmitters were identical to those used in the crane study in Japan, and were attached to the backs of the cranes with Teflon ribbons.

One White-naped Crane was successfully tracked to its wintering ground, though the tracking of the other two birds was unsuccessful. The "successful" crane migrated south, and stayed at the mouth of the Yellow River (37.7°N, 118.7°E) for about 20 days. He then went south through the west of Nanjin (32.1°N, 116.8°E) to Lake Poyang (29.1°N, 115.9°E), a well known wintering ground for Siberian White Cranes Grus leucogeranus. The accumulated tracking distance was 2,349 km. It took 65 days to reach Lake Poyang from Daursky. The life of the battery was about 110 days.

In February 1992, smaller transmitters (45-55 g) were attached to four Hooded and six White-naped Cranes migrating north from Izumi, Japan (Higuchi et al. 1992). The transmitters were also developed by NTT, and were attached to the backs of the cranes with Teflon ribbons (Fig. 1). The batteries are expected to last for about six months.

Four White-naped and two Hooded Cranes were successfully tracked to their breeding grounds. All the four White-naped Cranes migrated through the Korean Peninsula to the Sanjiang Plain of north-eastern China (Fig. 1). Crucial resting areas were the North Korean-South Korean border, some wetlands along the east coast of North Korea, and around Lake Khanka in Russia. The accumulated tracking distance was 2029, 1820, 2580, and 2290 km for the four White-naped Cranes. It took 17-42 days to reach their breeding grounds from Izumi, Japan.

Fig. 1: Migration routes of five white-naped cranes tracked from Izumi, southern Japan, in 1992. Higuchi et al. (1992).

The two Hooded Cranes migrated through the Korean Peninsula and the Sanjiang Plain to around Tyrma (49.9°N, 132.8° E) and Imeni Poliny Osipenko (53.6°N, 135.9°E) in south-eastern Russia. Crucial resting areas were some wetlands along the west coast of South Korea and North Korea, and the Sanjiang Plain. The accumulated tracking dis-tances for the cranes were 3167 and 3800 km. It took 32-38 days to reach their breeding grounds from Izumi.

In the two families of White-naped Cranes, the breaking up process of the family was traced. In one family, the parent and the young separated soon after arriving at the breeding ground (Fig. 2), while the other family had already broken up during their migration.

Fig. 2: Distances between white-naped crane parents and young during the course of migration. The arrow is when the cranes reached their breeding sites. Higuchi et al. (1992)

It was very impressive to discover, through satellite tracking, that certain country borders, and the DMZ, are crucial for migrating birds. Those borders were established by people, and so were meaningless for migrating birds. However, it is very difficult or impos-sible for people to enter or develop such borders and their neighboring areas. As a consequence, some borders such as the DMZ of the Korean Peninsula are now unofficial sorts of sanctuaries or nature reserves for migrants. Those areas seem to be getting more and more important for wildlife, because the surrounding areas are being heavily developed.

We are studying the habitat charac-teristics and conservation measures of crucial resting, breeding, and wintering grounds shown in this study. Landsat data and ecological surveys are used to analyze habitat characteristics.

Cooperative work with researchers and conservationists in many countries will be very important for considering conservation measures which will be derived from this satellite tracking study.

I thank the following colleagues for coworking in the field and the laboratory: Kiyoaki Ozaki, Go Fujita, Jason Minton, Masaki Soma, Noboru Kanmuri, Mutsuyuki Ueta, K. Golovuskin, Oleg Goroshuko, Vladimir Krever, V. Ilyashenko, Vladimir Andronov, George Archibald, Jim Harris, Sergei Smirensky and Steven Landfried.

• Higuchi, H., Sato, F., Matsui, M., Soma, M., and Kanmuri, N. 1991a. Satellite tracking of the migration routes of Whistling Swans Cygnus columbianus. Journal of the Yamashina Institute for Ornithology 23:6-12.

• Higuchi, H., Sato, F., Matsui, M., Soma, M., and Kohiyama, K. 1991b. Satellite tracking of the migration routes of Whistling Swans. Biotelemetry XI:100-103.

• Higuchi, H., Ozaki, K., Fujita, G., Soma, M., Kanmurui, N., and Ueta, M. 1992. Satellite tracking of the migration routes of cranes from southern Japan. Strix 1:1-20