 San Diego Zoo, Natural Research and Magadan Zapovednik (State Nature Reserves are called “zapovedniks” in Russia) teamed back in 2006 to track young Steller’s sea eagles via satellite, and continue long-term surveys and monitoring of eagles on the breeding grounds. Since then Los Angeles Zoo, Denver Zoo and Hogle Zoo have joined the effort. Surprisingly, very little is known about the period of time prior to breeding for any eagle species, and this undermines conservation. (See this: http://www.sandiegozoo.org/news/stellers_sea_eagle_tracking.html).
During the period 2006-2008 we fitted 15 nestling Steller’s sea eagles with satellite-received transmitters. Apparently, only two of these birds survived past their first year, and humans were implicated in the deaths of a number of them. For example, we found the transmitter (PTT 65629) near the nest site in 2007. Its harness had been cut. (See below). This was disappointing, but gave us pause because of so many of the tags being “lost” due to human persecution in this remote part of the world! Some birds died of natural causes with at least two of them apparently getting trapped by by the progress of winter when they did not move far enough south early enough.
 Of the two birds that did survive for some time, one that was tagged in 2006 spent its first winter on the southern-most Kuril Islands and on Hokkaido. In April 2007 it headed north and spent it first summer as an independent eagle on Sakhalin Island, mostly along the central east coast, an area of intense oil and gas development. It seemed to us that this place was potentially dangerous. In early November 2007 this bird headed south again and crossed onto Hokkaido and wintered again both ont the mainland of Hokkaido and on the southern Kuril Islands. On 8 March a professional photographer, Gaku Tozuka, took pictures (below) of this eagle on the Shiretoko Peninsula, clearly showing the antenna from the transmitter and the coded color band (5H) we fitted to the eagle as a nestling. On 29 March 2008, 65632 started on migration north and again spent its summer on Sakhalin, mostly along the central east coast. In early April 2008, 65632 crossed north to Sakhalin, and spent most of the spring and summer on the lagoons that are on the east coast of that island. During the summer it made some excursions to the north of Sakhalin and it went off the air on 27 August 2008 in north central Sakhalin.Visit this site to learn more about the part of Sakhalin where our eagle spent his first summer as a free-flyer: http://www.sakhalin.ru/Engl/Region/cities.htm.
Of the five birds fitted with satellite tags in 2008, only one apparently survived its first year, 65629. It left on its first southerly migration on 18 September and around New Year settled into its wintering area on the Russian mainland near the town of Terney on the Russian coast of the Sea of Japan. It made a small move back north (~150 km) and settled in for the winter. It started its northward migration on 8 April and on 27 May it reached its apparent summering area on the Russian mainland near Ayan (Ayan has a Wikipedia entry…have a look! http://en.wikipedia.org/wiki/Ayan).
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Steller's sea eagle ID 65632 on Shiretoko Peninsula, Japan, 8 March 2008. Copyright G. Tozuka
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We remain surprised that such a large proportion of the birds we tagged have apparently died, and that in most cases the culprits in those deaths are humans! Steller’s sea eagles face many threats. There was the lead poisoning threat of the 1990’s, and there is the constant pressure (as yet unmeasured) of purported overfishing. The fossil fuel energy developments of Sakhalin and the windfarms of Hokkaido are a worry. On top of this, eagles have a naturally high mortality in their first year. We always knew that there would be some direct human persecution. Although few people live in these areas, most have guns and many are very bored. Because of this and despite the fact that not everyone out there shoots eagles, if our sample is representative, we should be worried!
We will be updating this page periodically as we recieve more data, so visit again. Click here to vist the archive of maps that show the birds progress. With the continuing help of San Diego Zoo, we will be working on the breeding grounds in Magadan in 2008. We are also doing some pilot work on the Kamchatka Peninsula.
Figure 1. Movements by a 21 month old Steller's sea eagle between mid November 2007 and 29 March 2008 (its second winter). This bird was fitted with a satellite tag in 2006.
Published papers arising from this work:
Ueta, M., McGrady, M.J. Nakagawa, H., Sato, F., and Masterov, V. 2003. Seasonal change in habitat use in Steller’s sea eagles. Oryx 37(1): 110-114.
McGrady, M. J., M. Ueta, E. Potapov, I. Utekhina, V. Masterov, A. Ladyguine, V. Zykov, J. Cibor, M. Fuller, W.S. Seegar. 2003. Migration and wintering of juvenile and immature Steller’s sea eagles. Ibis 145: 318-328.
Potapov, E., McGrady, M., Utekhina, I., and Garcelon, D. 2001. Numbers and trends in Steller’s sea eagle: a review. Abstracts of 4th Eurasian Congress on Raptors. Seville 25-29 September 2001. p. 147.
McGrady, M. J., M. J. Ueta, E. R. Potopov, I. Utekhina, V. B. Masterov, M. Fuller, W. S. Seegar, A. Ladyguin, E. G. Lobkov & V. B. Zykov. 2000. Migration and wintering of juvenile and immature Steller’s sea eagles. Pp. 83-90. In: Ueta, M. J. and M. J. McGrady (Eds.) First Symposium on Steller’s and White-tailed Sea Eagles in East Asia. Wild Bird Society of Japan. Tokyo.
Potopov, E. R., I. Utekhina & M. J. McGrady 2000. Steller’s sea eagle in Magadan District and in the north of Khabarovsk District. Pp. 29-44. In: Ueta, M. J. and M. J. McGrady (Eds.) First Symposium on Steller’s and White-tailed Sea Eagles in East Asia. Wild Bird Society of Japan. Tokyo.
Utekhina, I., E. Potopov & M. J. McGrady 2000. Diet of the Steller’s sea eagle in the northern Sea of Okhotsk. Pp 71-82. In: Ueta, M. J. and M. J. McGrady (Eds.) First Symposium on Steller’s and White-tailed Sea Eagles in East Asia. Wild Bird Society of Japan. Tokyo.
McGrady, M., Potapov, E., and Utekhina, I. 1999. Feeding on Steller’s sea eagle (Haleaeetus pelagicus) nestling by a brown bear (Ursus arctos). Journal of Raptor Research 33 (4): 342-343.
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For more information please contact mike.mcgrady@natural-research.org
Photos copyright M. McGrady
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