 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. Our aims were two-fold. First, we wanted to track eagles in the years prior to becoming breeders (large eagles like the Steller’s sea eagle take four years or more to come into adult plumage). Surprisingly, very little is known about this period of time for any eagle species, and this undermines conservation. This is particularly true for Steller’s sea eagle because its population is relatively small (probably naturally so) and it breeds in remote areas so its breeding numbers are not closely monitored. We also wanted to use the movements of Steller’s sea eagles and the nature education expertise and San Diego Zoo as a tool for public conservation awareness (See this: http://www.sandiegozoo.org/news/stellers_sea_eagle_tracking.html).
In 2006 we fitted five nestling Steller’s sea eagles with satellite-received transmitters. Four of these birds started on their migration, one most probably died at the hands of humans near its nest, roughly one month after fledging (We found the transmitter (PTT 65629) near the nest site in 2007. Its harness had been cut. See below).
As we tracked the eagles, two others also seemed to be victims of human activity. One tag (65633) suddenly stopped transmitting near a village on the Russian coast south of Vladivostok, at the border of the Botchanskiy Strict Nature Reserve. The other (PTT 65631) is, even now transmitting from the edge of a fishing village of Chumikan near the mouth of the Amur River in Russia. It was apparently shot at a fisheries near the mouth of a small river some 20 km NE from the Chumikan village (not far from the Antykan river) A third bird that did start its migration was also “lost” near Shantar Island (probably on ice floe near one of a small island of “Sivuchi Kamni” (Sea Lion’s Rocks).
So, we were left with a single active transmitter on a live bird by the end of 2006. 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! So, 65362 migrated south along the Russian mainland and jumped across to Sakhalin Island (directly north of Hokkaido) in late November 2006. From there it continued south crossing the La Perouse Strait to Hokkaido around Christmas time. It then jumped to across a short and maybe frozen stretch of sea to two islands off the NW coast of Hokkaido, Rishiri-to and Rabun-to, where it spent its first winter.
 In early April 2007, 65632 headed north across the La Perouse Strait again for its first summer as an independent eagle! It spent most of the spring in southern Sakhalin, and then in early June 2007 it pushed farther north, about half way up the eastern seaboard. We were a bit concerned about this because this is in the heart of the oil and gas development area of Sakhalin. It seemed to us that this place was potentially dangerous. 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. (We’ll pick up this thread of the story later. Read further.)
Change scene… in late July 2007, almost 1000 km (600 miles) north we were back in the field on the breeding grounds, surveying breeding pairs on the rivers and the coast near Magadan. We surveyed stretches of the Kava and Chelomdza Rivers that are within the Magadan Zapovednik, the Tauy River and the coast west of the village of Balagonoe, including Motykley Bay and Talan Island. Of the thirty some territories on the rivers, although all were almost all occupied, only one had produced a chick. We think this lack of productivity in this year was due to heavy rains that may have affected survival of eggs and hatchlings or influenced the hunting of the adults. In contrast, the great majority of the the twenty or so territories that we surveyed on the coast had large chicks. We fitted five nestlings with GPS satellite transmitters and left them to grow up, fledge and start their first migration south (See map below).
 So, summer passed and migration time came. Four of the five birds we fitted with tags in 2007 left their nest sites. One bird apparently died or lost its tag near the nest. We should find out when the weather clears and we can visit the site this comingsummer. One bird died at the Arman River, one on the coastal slope of the Sheltinga Bay. We do not know whether humans were involved in these losses, but this part of the Arman River is where caviar harvesting operations occur. At both of these places there are lots of discarded fish carcasses, so plenty of food, so we can not imagine them dying of hunger!
Two birds started on a “normal” migration. Well one did; the other (42678) made a big victory lap around various rivers to the north and east of its natal range before setting off on a proper southward migration around the end of October. By late November this bird was near the village of Fedorovskoe where, the evidence from the tag’s transmissions, suggests it was apparently killed. This village and the nearby area of sea is under the nominal protection of the Dzugdzhur Strict State Nature Reserve, and this incident may serve to illustrate how difficult it is to police these places.
At the end of 2007 were were left with one, live bird from 2007 that seems to be transmitting, and the prognosis did not look bright. That bird (42680) was sitting on the Okhota River, some distance inland with winter is closing in and food likely getting scarce. That bird tried to make a break for it in early 2008, and made it as far as the coast near Magadan. Apparently, it perished soon thereafter, probably because it could not find enought to eat. In 1997 we also tracked some eagles, and one bird behaved in exactly the same manner. Sadly, it apparently perished when it found itself without food and too far from ice-free water where it might hunt. Back then one could almost feel winter closing in on it as time passed. It survived until the end of January.
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Steller's sea eagle ID 65632 on Shiretoko Peninsula, Japan, 8 March 2008. Copyright G. Tozuka
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Oddly, in early October, 65632 (Remember it? …the bird marked in 2006 that spent its first full summer in east central Sakhalin…?) headed north to the northern tip of Sakhalin for about two weeks before returning to the eastern seaboard. In early November 2007 this bird headed south again and crossed onto Hokkaido around 11 November. Rather than returning to where it wintered in 2006-2007, it headed along the NE coast of Hokkaido and then jumped back into Russian territory on the southern Kuril Islands, where it stayed until mid January 2008 when it moved back to Hokkaido and spent a couple of weeks along the south coast near Moraito. By the end of January though it had moved to back into Russian territory on Rausu Island, and from early February until late March was hopping between there and the Shiretoko Peninsula on Hokkaido. During that time (8 March) a professional photographer, Gaku Tozuka, took pictures (right) 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. (The Shiretoko Peninsula is famous for the Steller’s sea eagles that winter there, although the concentration of eagles has lessened in the last 20 years as numbers of sika deer have increased elsewhere on Hokkaido and thier carcasses have provided food, and the amount of fish available to eagles near Shiretoko has (perhaps) decreased.) On 29 March 2008, 65632 started on migration (we think) and made it first move away from its wintering ground and was about 120 km (90 miles) west.
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. 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.
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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