S42.1: Satellite tracking cranes and the conservation of their habitats

1 Laboratory of Wildlife Biology, School of Agriculture and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan; ² Research Center, Wild Bird Society of Japan, Minamidaira 2-35-2, Hino-shi, Tokyo 191-8657, Japan

In East Asia, cranes migrate thousands of kilometres through several different countries, which makes study of migration routes logistically difficult due to political boundaries as well as distances. However, showing migration routes and important migratory rest-sites is crucial for the conservation of cranes. Without such information, we cannot make concrete action plans on where and how to conserve.

Crane migration studies have been done using leg bands (Ozaki 1991a, b; Shibaev and Surmach 1994), but have been limited in scope due logistical and political challenges. Recently, satellite transmitters (platform terminal transmitters; PTTs) became light enough to use on large species of birds, which should carry an extra load of no more than 4% of their body weight (Brander & Cochran 1971).

Satellite tracking East Asian cranes first began in early 1991 for White-naped Cranes Grus vipio and Hooded Cranes G. monacha migrating from their wintering grounds in Izumi, on the southern coast of Kyushu Island, Japan (Higuchi et al. 1992). Further tracking from other sites and during subsequent years have provided information on several migration routes in the region (Higuchi et al. 1994, 1996). The species included Red-crowned G. japonensis, Siberian G. leucogeranus, Common G. grus, and Demoiselle Cranes Anthropoides virgo, and a total of about 70 cranes were tracked so far.

In this paper, we summarise and review the results of our satellite tracking studies (Higuchi et al. 1992, 1994, 1996, in press), and the results of satellite image analyses which utilised the tracking data (Kanai et al. 1994; Kondoh et al. 1994), in order to clarify the present state of research on migration and conservation of cranes in East Asia. We would like to focus on White-naped Cranes migrating from southern Japan and Red-crowned Cranes migrating from Russia, which have provided good data in terms of sample sizes.

A total of 14 White-naped Cranes were captured to deploy transmitters in Izumi, Kyushu, Japan (32° N, 125° E) in January and February of 1992 and 1993. Izumi is a well-known wintering site of White-naped and Hooded Cranes (Higuchi 1991; Ozaki 1991a). It faces the Yatsushiro Sea on one side and low hills border the other. Cranes feed in about 2,500 ha of developed agricultural fields, and within that area there is a 51 ha artificial feeding site.

A total of 14 Red-crowned cranes were captured in Russia at Khingansky Nature Reserve in 1993, and at Lake Khanka Nature Reserve in 1993 and 1994. Khingansky Nature Reserve lies along the Amur River near Blagoveschensk City in the Russian Far East, it is closely associated with the nearby Ganukan Wildlife Reserve, and together the two are designated Ramsar Sites. In this paper, Khingansky refers to the combined area of the two reserves. Khingansky contains 97,300 ha of marshland, about one-third its total area, and the remaining area is forest. Lake Khanka N. R. is on the shores of Lake Khanka in the southeast of the Russian Far East, north of Vladivostok. The refuge contains 111,500 ha and consists mainly of marshland.

Transmitters used in our study were developed by the Nippon Telegraph and Telephone Corporation (NTT). Either of the two types of transmitter, T-2038 and T-2050, was attached to the back of cranes with Teflon treated ribbon. The type T-2038 was 133x33x23 mm in size with an antenna of 200 mm, and weighed 105 grams. A transmitter of T-2038 and its harness weighed about 120 g, which is about 1.5-2.0% of the body weight of an adult White-naped or Red-crowned Crane. The type T-2050 was 60x40x30 mm in size with an antenna of 180 mm, and weighed about 80 grams. A transmitter of T-2050 and its harness weighed about 95 g, which is about 1.2-1.5% of the body weight of an adult White-naped or Red-crowned Crane.

All transmitters cycled at six hours active and 12 hours inactive, and the pulse interval was 60 seconds. The battery life was expected to be three to six months for all transmitters. Actual battery life varied among transmitters.

Location classes range from zero to three (Service Argos 1994). The higher the location class, the more accurate the location. In the case of location data received from PTTs designed for tracking ungulate mammals and wolves, location classes one, two and three had a one standard deviation accuracy of 1,188; 903; and 361 m (Keating et al. 1991). According to Service Argos (1994), class one and two locations offer a one standard deviation accuracy of 1,000 and 360 m, respectively, for stationary transmitters. In our analyses, we assume an accuracy of 1 km for all data of location class one and above, which means that we will not use satellite locations for movements within 1 km.

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

The period of stay at a particular site was calculated as the difference between the first day of arrival at the site and arrival at the next site. Locations of the cranes are presented below as longitude and latitude, and represent the range of coordinates received during their stay in each area. The most southern and northern latitudes received, and the most western and eastern longitudes, are reported when more than one location was received.

General habitat characteristics of stopover sites were obtained from published materials such as Scott (1989), Ma & Li (1994), Fan et al. (1994) and maps available from the Defence Mapping Agency of the US. Landsat satellite images were used to show the habitats of some important crane sites.

In 1992 and 1993, nine of the 13 White-naped Cranes were successfully tracked from Izumi to their breeding ground. Two migration routes were shown. The western route to Zhalong Nature Reserve (China) was shown by only 2 individuals during 1993, but the eastern route to the Three Rivers Plain and the Amur River Basin was followed in both years by a total of 7 individuals.

Cranes migrating from Izumi spent their first rests at the two rest-sites in the DMZ: Panmunch'om and Ch'olwon. Those rest-sites showed heavy use, because 7 of 9 tracked cranes rested there, and 5 of those rested for more than 50% of their total migration period.

Along the western route, two cranes migrated to Zhalong Nature Reserve of Heilongjiang Province in northeastern China, and are outstanding because the Panmunch'om rest-site was their only lengthy rest along the entire migration route. The two cranes travelled 2,170 km and 2,377 km in 29 and 62 days, respectively.

On the eastern route, 7 successfully tracked cranes flew along the east coast of the Democratic People's Republic of Korea (DPRK; North Korea). Six of them rested in Kumya of North Korea, and then flew to Lake Khanka in Russia. One juvenile spent nearly 50% of its migration period (about 1 month) at the Lake. From Lake Khanka, 7 cranes flew to areas in the Amur River Basin, including the Three Rivers Plain of Heilongjiang Province in China. It was the destination, and the cranes probably bred there.

The 7 cranes on this route traveled 2279.1±307.6 (s.d.) km (range= 1,820-2,728 km) during 43.7±27.2 (s.d.) days (range=17-85 days).

Cranes captured at two different sites took different migration routes with separate chains of rest-sites and wintering areas. The route from Lake Khanka led to wintering grounds on the Korean Peninsula, and a total of seven cranes were tracked the entire distance along this eastern route in 1993 and 1994. The route from Khingansky led to coastal China, and two cranes were tracked the entire distance along this western route in 1993.

On the eastern migration route from Lake Khanka, the seven successfully tracked cranes flew about 300 km southwest to an extensive area of wetlands around the Tumen River mouth in Russia. Six cranes stopped over there. From the Tumen River, cranes migrated south along the coast of North Korea until they reached the river mouth at Odaejin-nodongjagu. After reaching the coast again at Kimchaek, they flew south along the coastline toward Kumya.

Within 125 km of each other, there are three identified wintering sites: Kumya, Anbyon and Ch'olwon. A total of seven tracked individuals wintered at these sites. One individual wintered exclusively at Kumya, and four cranes wintered exclusively at Ch'olwon after resting for some days at either Kumya or Anbyon. Two cranes followed a complex pattern of commuting between the three sites during the winter season.

The total migration distance on this eastern route was 874.4±62.3 S. D. km (range= 775.5-948.2 km) for the five cranes that did not show movements among the wintering areas. The cranes took 5.6±2.4 days (range= 3-9 days, N=5) to migrate between breeding and wintering areas.

On the western migration route, the two successfully tracked cranes went down to Panjin Marsh at the head of Bohai Bay in China. They flew to coastal mud flat area south of the city of Tangshan, and then flew across Bohai Bay to reach the Yellow River Estuary. Departing the Yellow River Estuary, the cranes went south until reaching the coastal area of Jiangsu Province (China), known as the Yancheng Marshes. They wintered there.

The two cranes migrating from Khingansky traveled 2.5 times the mean distance of eastern migrants, 2,241.8 km, and took more than 20 days (x = 29.5) to finish their migration.

In some cases, location data from White-naped Cranes continued to be received after migration had obviously stopped. This data, from an adult and two juveniles, showed different patterns of habitat use which appeared to be based on age. The adult, being of breeding age, kept its position in a marsh along the Inner Qixing River, where it logically had built its nest (Higuchi et al. 1992). The crane was never located outside the marsh.

The daily movements of Red-crowned Cranes showed a clear pattern at the Ch'olwon wintering site. Ch'olwon lies within the DMZ, which is off-limits to normal human activity, and the CCZ in which land use and movements of people are controlled by South Korea.

Six cranes were located at the Ch'olwon site, and of those, the four which did not commute provided enough data to compare day and night locations. The cranes tended to use the CCZ during the day, therefore as a foraging site, and use the DMZ at night, therefore as a roosting site. Three cranes were located in the CCZ during 66.7% to 100% (x = 85.2) of their day locations received. One crane was an exception to this pattern, being located there only 14.3% of the time. Three cranes sent 92.6 (77.8-100)% of their night locations from the DMZ. One crane proved to be an exception to the pattern, being located only 16.7% of the time in the DMZ.

There is a difference in habitat types between the DMZ and the CCZ. The DMZ, where cranes mostly roost, is an area of low hills and meadows with vegetation such as bushes and grass. Natural streams are present, and appear to provide the roosting sites that the cranes prefer. The CCZ is a developed area of irrigated agricultural fields. The fields provide an abundance of waste grain that remain after harvest (Pae & Won 1994). Thus, the CCZ provides an abundance of agricultural food, and the DMZ provides safe roost sites in natural streams.

For most crane individuals, the normal migration pattern relies on suitable rest-sites between the wintering and summering ranges. These sites can be considered important international airports for the migrating cranes. The cranes rest their wings and take energy there to leave for the next site. If these sites are lost, the cranes may not be able to complete their migration.

Using information gained by satellite tracking, researchers and conservationists have had some success in protecting those rest-sites and summering areas. In the Three Rivers Plain, which is a summering site for White-naped Cranes, satellite tracking data is being used to protect the remaining marshland habitat. Agriculture in the plain is being actively expanded by the Chinese Government, with funding assistance from Official Development Assistance (ODA) and other loan sources such as the World Bank. The Wild Bird Society of Japan and the International Crane Foundation are working with the Overseas Economic Cooperation Fund (OECF) of the Japanese Government in order to locate development away from sensitive marshlands.

Based on the satellite tracking information for White-naped Cranes and for that of Hooded Cranes (not discussed here), the Center for Nature Protection of DPRK has worked to establish Kumya and Mundok (a west coast rest-site used by Hooded Cranes) as special Migratory Bird Protection Areas. In December of 1995 the DPRK Government did so, making those the first sites in DPRK protected especially as migration rest-sites.

The Korean DMZ harbors two crucial crane sites, Panmunch'om and Ch'olwon. For example, eleven out of the 13 White-naped Cranes tracked rested for more than 10 days at one or both of these sites. The ROK Government is considering the establishment of a nature reserve for cranes in the CCZ area south of the DMZ. This area is important as a rest-site for White-naped Cranes and as a wintering site for Red-crowned Cranes. Its protection is important, as development has slowly been increasing in this valley which will prove to be an important linkage point between DPRK and ROK when and if the two sides begin reconciliation.

The Yellow River is a site which will also require protection, both for migratory Red-crowned Cranes and migratory White-naped Cranes (Higuchi et al. 1994). Although development pressure is not heavy in this area, the ecology of the area may have many negative impacts. For instance, it is said that the Yellow River ceased to flow into the sea during a period in 1996. Field research and a larger sample size of tracked cranes may be required in order to plan conservation of the area.

We must conserve these important sites as a network, not separately. The conservation of these areas must be approached from an international perspective, because the migration routes themselves cross several national boundaries. Satellite tracking data should be useful to promote international cooperation for conservation of migrating cranes and their habitat.

We sincerely thank our colleagues in Japan, Russia, China, North Korea, South Korea, and the USA, who worked with us in the field and laboratory or gave us valuable advice and information on cranes and wetlands. We are grateful to Jason Minton for helping with preparing the draft. This research was supported by the Yomiuri Newspaper Company, the NEC and NTT Corporations of Japan.

Brander, R. & Cochran, W. 1971. Radio-location telemetry. In Wildlife Management Techniques, 3rd ed. (ed. R. Giles), pp. 95-103. The Wildlife Society, Washington D.C.

Fan, Z., Liang, Y., Zhang, Y., Jin, L. & Qui, Y. 1994. Distribution and conservation of cranes and wetlands in Jilin and Liaoning Provinces, northeast China. In: The Future of Cranes and Wetlands (eds H. Higuchi & J. Minton), pp. 136-140. Wild Bird Society of Japan, Tokyo.

Higuchi, H. 1991. Cooperative work on crane migration from Japan to the U.S.S.R. through Korea and China. In: Salathe, T. (ed.) Conserving Migratory Birds: 189-201. Cambridge, U.K.: International Council for Bird Preservation.

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

Kanai, Y., Kondoh, A. & Higuchi, H. 1994. Analysis of crane habitat using satellite images. In: Higuchi, H .and Minton, J.(eds) The Future of Cranes and Wetlands: 72-85. Wild Bird Society of Japan, Tokyo.

Kondoh, A., Kanai, Y. & Higuchi, H. 1994. The theory and practice of environmental analysis through Landsat images. In: Higuchi, H. and Minton, J. (eds) The Future of Cranes and Wetlands: 61-71. Wild Bird Society of Japan, Tokyo.

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

Ma, Y. & Li, X. 1994. The population and habitat of cranes in China's nature reserves. In: Higuchi, H. & Minton, J. (eds) The Future of Cranes and Wetlands: 141-145. Wild Bird Society of Japan, Tokyo.

Ozaki, K. 1991a. Returns and recoveries of Hooded and White-naped Cranes banded in winter at Izumi, Japan. In: Harris, J. (ed.) Proceedings 1987 International Crane Workshop Qiqihar, China: 311-314. International Crane Foundation, Baraboo, Wisconsin.

Ozaki, K. 1991b. Migration studies of the Hooded and White-naped Crane in East Asia. In: Maruyama, N. (ed.) Wildlife and conservation-present trends and perspectives: 181-184. Japan Wildlife Research Center, Tokyo.

Scott, D.A. 1989. A Directory of Asian Wetlands. International Union for the Conservation of Nature, Cambridge.

Service Argos. 1994. User Manual . CLS/Service ARGOS, Toulouse.

Shibaev Y. & Surmach S. 1994. Autumn migration of Red-crowned Cranes Grus japonensis and G. vipio in the Primorye Region, Far East Russia. In: Higuchi, H. & Minton, J. (eds) The Future of Cranes and Wetlands: 114-120. Wild Bird Society of Japan, Tokyo.