S49.1: Satellite tracking of migrant swans and eagles wintering in Japan

1Research Center, Wild Bird Society of Japan, Tokyo, Japan 191-0041, e-mail KGB00707@niftyserve.or.jp; ²Laboratory of Wildlife Biology, School of Agriculture and Life Sciences, The University of Tokyo 113 - 8657, Japan; ³Bird Migration Research Center, Yamashina Institute for Ornithology, Tsutsumine, Abiko, Chiba 270-1145

Japan has many migratory birds both in the summer and winter, because Japan is located in the middle of Eastern Asia. Habitats of migratory birds, wetlands, forests and others, have been decreasing or deteriorating in Japan and in many parts of Asia. To conserve the migratory species and their habitats it is important to know their migration routes. There has been only fragmentary information on the migration routes, based on observations of metal-ringed and collar-marked individuals (Yamashina Institute for Ornithology Bird Migration Research Center 1986 - 1997).

In Asian countries only few persons observe birds compared to the size of each country. Sometimes political relationships between countries prevents the exchange of information about bird migration.

Satellite tracking is an effective way to show the migration routes and ecology of birds (Jouventin and Weimerskirch 1990, Nowak et al. 1990). Nippon Telegraph and Telephone Corporation (NTT) and Toyo Communication Equipment Co., Ltd. (TOYOCOM) has developed small transmitters (Platform Transmitter Terminals or PTTs) for ARGOS system that can be attached to birds. Wild Bird Society of Japan and collaborators have conducted satellite tracking studies of Whistling Swan Cygnus columbianus (Higuchi et al. 1991), Whooper Swan C. cygnus (Kanai et al. 1997), White-tailed Sea-Eagle Haliaeetus albicilla (Veta et al. 1988) and Steller's Sea-Eagle H. pelagicus (Ueta et al. in press) and cranes (Higuchi et al.1992, Higuchi et al. 1994, Higuchi et al. 1996, Higuchi et al. In press). In this paper, we would like to summarize our tracking results of swans and eagles.

Four Whistling Swans were fitted with PTTs on April 10, 1990, at Lake Kuccharo, near the northern tip of Hokkaido (45.1 N, 142.3 E). Lake Kuccharo is a well known resting site of Whistling Swans. More than 10,000 swans stop over in spring and autumn.

The size of PTT (T2038) was 112 x 35 x 19 mm with a 187 mm antenna, and its mass was 83g. The antenna was a solid wire for one transmitter and a flexible wire for the other three. Two PTTs cycled at six hours active - 12 hours inactive and the other two PTTs cycled at three hours active - six hours inactive. The pulse interval was 60 seconds for three PTTs, and 90 seconds for the other. The battery life was about two months. Two PTTs were set by leather harnesses with Teflon tubes, one was glued by epoxy resin adhesive on the back and one was attached on a neck collar band.

Fifteen Whooper Swans were captured on the Kominato sea coast (40.9 N, 141.0E), northern Honshu, Japan, on February 21, 1994 and February 23, 1995. Kominato is a well known wintering site of Whooper Swans, and is designated as a national natural monument in Japan. About 400-500 Whooper Swans winter at Kominato each year. Six PTTs (T2050) used in 1994 were 60 x 40 x 30 mm in size with an antenna of 187 mm, and weighed 80g. Nine PTTs (T2050) used in 1994 were 70 x 34 x 23 mm in size with an antenna of 187 mm, and weighed 65g. The pulse interval of all transmitters was 60 seconds. All PTTs in 1994, and seven of nine PTTs in 1995, cycled at six hours active and 12 hours inactive. The battery life was expected to be six months. Two PTTs in 1995 cycled at six hours active and 42 hours inactive, and battery life was expected to be one year. Transmitters were harnessed to the back of swans with Teflon-treated ribbons.

Two White-tailed Sea-Eagle and one Steller's Sea-Eagle were captured in Oshima Peninsula (42.2 N, 140.2 E), southern Hokkaido on December 26, 1995 and January 23, 1996. The PTTs (T2050) were 70 x 34 x 23 mm with an antenna of 187 mm, and weighed 65g. The PTTs cycled at six hours active and 42 hours inactive, and battery life was expected to be one year. Transmitters were harnessed to the back of the eagles with Teflon-treated ribbons.

Location data were received through computer communications and on disks sent from the CLS/Service Argos in France. Location classes (LC) ranged from 0 to 3. The higher the location class, the more accurate the location. Place names are based on ONC maps of the Defense Mapping Agency Aerospace Center.

All four swans went north along Sakhalin, and stopped in northern Sakhalin or around the mouth of the Amur River in Russia. They spent some time there before proceeding further north. One female swan with a glued PTT (6 hours active, 60 seconds pulse interval) was successfully tracked to its breeding range in the arctic region (Fig. 1).

This swan arrived in southern Sakhalin (46.8 N, 142.7 E) on April 26, 1990. She moved to northern Sakhalin (51.6 N, 143.3 E) on May 1, where she remained until May 9. She then went north (61.8 N, 152.3 E) on May 16, and arrived near the mouth of the Kolyma River (68.6 N, 161.3 E) on May 17. Time taken for migration from Lake Kuccharo to Kolyma River was 3 weeks. On May 18, she moved a little west and north (69.6 N, 160.8 E) and stayed there until May 22, when the battery quit. It is likely that the swan bred in this area. The accumulated tracking distance was 3,083 km. She returned with one young to Lake Suwa in central Honshu on November 17 of the same year. (Fig.1 )

Eight of the 15 Whooper Swans were successfully tracked to their breeding ground in Russia. They migrated from Kominato to their breeding sites via southeastern Hokkaido, northeastern Hokkaido, Sakhalin and the lower Amur River.

Two individuals spent the summer on the lower Amur River, two individuals summered on the north coast of the Okhotsk Sea, three individuals spent the summer on middle reaches of the Indigirka River, and one individual spent the summer on the lower Kolyma River. Migration routes of two individuals are described as follows (Fig. 1).

ID21416, tracked in 1994, was located for the last time in Kominato on March30, 1994. On April 1 it stayed on the Tokachi River (42.8 N, 143.5 E), and rested there for 10 days. The swan moved to eastern Aniva Bay (46.5 N, 143.3 E), southern Sakhalin via central Aniva Bay on May 18, and rested there for 13 days. It flew to the lower Amur River on May 9, and rested there (52.2-53.2 N, 139.5-140.5 E) for 20 days. It was located near Okhotsk City (60.0N, 144.1 E) on May 30, and rested there for 8 days. The swan moved to wetlands along the Indigirka River (67.9 N, 143.5 E) on June 18, and was located there until its PTT quit on July 25. The total migration time for this bird was 75 days. The accumulated tracking distance was 3,330 km. Most of the distance between resting sites were more than 100 km, the longest one was 760 km.

ID23395, tracked in 1995, was located for the last time in Kominato on April 7, 1995. The swan moved to central Aniva Bay on April 14 and eastern Aniva Bay in southern Sakhalin on April 25 via Akkeshi Lake and Furen Lake in eastern Hokkaido. It flew to Udyl Lake (51.6-51.9 N, 139.5-139.8 E), on the lower Amur River on May 7, and rested there for 22 days. The swan moved to wetlands along the Kolyma River (69.3 N, 152. 4 E) on June 10, and was located there until its PTT quit on August 9.

A total of 3,256 locations were obtained in 1994 and 1995 from Whooper Swans fitted with PTT T2050. LC1 (Location Class 1) data were 36 % of all locations. Total locations above LC1 were 58 %. LC0 data were 29 % of all locations (Fig 2).

Keating et al. (1991) calculated the accuracy of LC 1, 2 and 3 data from PTTs designed for ungulates and wolves. Their one-standard-deviation accuracy results, compared to the accuracy's reported by the CNES/Argos (1992) were, respectively, 1,188 m versus 1,000 m for LC 1, 903 m versus 350 m for LC 2, and 361 m versus 150 m for LC3. In our analyses we assumed an accuracy of 1 km for all data of LC 1 and above.

Location class 0 data were included to show the general migration routes when the locations were considered appropriate from the nearest locations and elapsed time. They were, however, excluded from the analysis when more accurate locations were required.

Whooper Swans migrated from Kominato to southeastern Hokkaido, and rested there for a long time. They moved to Sakhalin via northeastern Hokkaido, and went north along Sakhalin. They crossed the Okhotsk Sea and moved to breeding areas. The migration routes of Whistling Swans from Sakhalin to breeding areas were similar to those of Whooper Swans. However, the migration routes from Honshu to Sakhalin were different. Whistling Swans migrated from Honshu to Sakhalin via the Japan Sea coast of Hokkaido (Yamashina Institute for Ornithology 1996). On the other hand, Whooper Swans migrated from Honshu to Sakhalin via the Pacific Ocean coast of Hokkaido.

While the migration routes of Whooper and Whistling Swans from Sakhalin to their breeding areas were similar, there was a small difference in resting sites. Five of 8 tracked Whooper Swans rested at Aniva Bay from 2 to 34 days each. Only one of 4 tracked Whistling Swans rested there for 5 days. Aniva Bay appeared to be a more important rest-site for Whooper Swans rather than Whistling Swans. The lower Amur River was an important rest-site for both swan species. Five of 8 tracked Whooper Swans rested or spent the summer there for 20 to 40 days, and 2 of 4 Whistling Swans for more than 10 days each. Around the Indigirka River basin and Kolyma River basin, breeding grounds of swans wintering in Japan, swan populations are currently increasing. On the other hand, the swan population of the Lena River basin and more western area is very low. There is high possibility that the Lena River swan population has different migration routes from the Indigirka River basin and Kolyma River basin swans.

The two White-tailed Sea-Eagles took similar migration routes. They started their migration between February and March, 1995. White-tailed Sea-Eagles moved from southern Hokkaido to Sakhalin, went north along Sakhalin then flew along the coast of the Okhotsk Sea, and spent the summer in the center or northern parts of the Kamchatka Peninsula. The autumn migration routes were different from spring migration. The eagles migrated south along the Kamchatka Peninsula and the Kurile Islands, making a circuit of the Okhotsk Sea during the year. The Steller's Sea-Eagle migrated almost along the same route, up to the continental seaboard nearby the Shantarskiye Islands, as the White-tailed Sea-Eagle's migration route. Migration routes of a White-tailed Sea-Eagle (ID23392) and a Steller's Sea-Eagle (ID22449) are described as follows (Fig. 3).

On February 19, 1995, the White-tailed Sea-Eagle (ID23392) moved near Wakkanai, north end of Hokkaido (45.3 N, 142.2 E). Then the eagle moved to eastern Aniva Bay (46.6 N, 143.5 E), southern Sakhalin on February 29, and rested around Aniva Bay for 19 days. It flew to Aynskoye Lake (48.8 N, 142.2 E) on March 22, and rested there for 12 days. The eagle was located at the north end of Sakhalin (56.9 N, 142.6 E) on April 15, and arrived at central Kamchatka(55.3 N, 158.8 E) on May 1, and it remaining there until it started its autumn migration on October 12. This eagle moved to the south end of Kamchatka (51.7N, 156.9 E) on October 20, and rested there for 10 days. It arrived on Kunashiri Island on December 1, and moved to Yakumo, Hokkaido, a previous wintering site, on 9 December, 1995. The distance (2,244 km) and duration (57 days) of the autumn migration were shorter than those of spring migration (5,430 km, 84 days).

The Steller's Sea-Eagle (ID22449) moved north to Lake Kuccharo, north end of Hokkaido, and crossed over to Sakhalin. It migrated north along Sakhalin and arrived on the Syantarskiya Islands on April 29, 1995. About 1,000 eagles were observed in Japan (WGWS 1996), and in Wakkanai, 621 eagles were observed on migration to Sakhalin from March 21 to April 5, 1991 (Ito 1991). Most of the eagles wintering in Japan migrated north via Sakhalin, and spent the summer in northern Sakhalin and on nearby continental seaboards.

We have only few data for migration of Steller's Sea-Eagle. Meyburg and Lobkov (1994) show a Steller's Sea-Eagle's movement along the Kurile Islands. This route is similar to the satellite tracked White-tailed Sea Eagle route presented in this paper. There is a possibility that the migration route of Steller's Sea-Eagle is similar to that of the White-tailed Sea Eagle. (Fig.3 Migration routes of eagles)

We sincerely thank our colleagues in Japan, Russia, China, and the USA, who worked with us in the field and laboratory or gave us valuable advice and information on swans. We also thank M. Nagendran for reviewing the draft of this paper. This research was supported by the Japan Fund for Global Environment, Yaniuri Newspaper Company, the NEC and NTT Corporations of Japan. Satellite tracking of eagles was carried out as a research project under the Japan - Russia Migratory bird treaty conducted by Environmental Agency of Japan.

CNES/Service ARGOS, Inc. 1992. User Manual. CLS/Service Argos. Toulouse, France.

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

Higuchi, H., Ozaki, K., Fujita, G., Minton, J., Ueta, M., Soma, M. & Mita, N. 1996. Satellite-tracking White-naped Crane Grus vipio migration, and the importance of the Korean DMZ. Conservation Biology 10: 806-812.

Higuchi, H., Ozaki, K., Fujita, G., Soma, M., Kanmuri, N. & Ueta, M. 1992. Satellite tracking of the migration routes of cranes from southern Japan. Strix 11:1-20.

Higuchi, H., Ozaki, K., Golovuskin, K., Goroshko, O., Krever, V., Minton, J., Ueta, M., Andronov, V., Smirenski, S., Ilyashenko, V., Kanmuri, N. & Archibald, G. 1994. The migration routes and important rest-sites of cranes satellite tracked from south-central Russia. In: Higuchi, H. & Minton, J.(eds) The Future of Cranes and Wetlands: 15-25. Wild Bird Society of Japan,Tokyo.

Higuchi, H., Shibaev, Y., Minton, J., Ozaki, K., Surmach, S. , Fujita, G., Momose, K., Momose, Y., Ueta, M., Andronov, V. , Mita, N. & Kanai, Y. (in press) Satellite tracking the migration of Red-crowned Cranes Grus japonensis. Ecological Research

Ito, M. 1991. Migration of Steller's Sea Eagles and White-tailed Sea Eaglesin Soya cape. Survey of the status and habitat conditions of threatened species, 1990. 45-49. Environment Agency, Tokyo, Japan. (In Japanese)

Jouventin, P. & Weimerskirch, H. 1990. Satellite tracking of Wandering albatrosses. Nature 343:746-748.

Kanai, Y., Sato, F., Ueta, M., Minton, J., Higuchi, H., Soma, M., Mita, N. & Matsui, S. 1997. The migration routes and important rest sites of Whooper Swans satellite tracked from northern Japan. Strix 15: 1-13.

Keating, K.A., Brewster, W. G.  & Key, C.H. 1991. Satellite telemetry: Performance of animal tracking system. J. Wildl. Manage. 55:160-171.

Meyburg, B.U. & Lobkov, E.G. 1994. Satellite tracking of a juvenile Steller's Sea Eagle Haliaeetus pelagicus. Ibis 136:105-106.

Nowak, E., Berthold, P. & Querner, U. 1990. Satellite tracking of migrating Bewick's Swans. Naturwissenschaften 77:549-550.

Ueta, M., Sato, F., Lobkov, E.G. & Mita, N. 1998. Migration route of White-tailed Sea Eagle Haliaeetus albicilla in northeastern Asia. Ibis 140:684 - 686

Ueta, M., Sato, F., Nakagawa, H. & Mita, N. in press. Migration routes and differences of migration schedule between adult and Young Steller's Sea Eagles. Ibis.

Working Group for White-tailed Sea Eagles and Steller's Sea Eagles (WGWS). 1996. Wintering status of Steller's Sea Eagles and White-tailed Sea Eagles innorthern Japan. Survey of the status and habitat conditions of threatened species, 1995. 1-9. Environment Agency, Tokyo, Japan. (In Japanese with English summary)

Yamashina Institute for Ornithology Bird Migration Research Center. 1986-1997. Report of the Bird Migration Research Center, 1986 - 1997. Yamashina Institute for Ornithology, Abiko.