Friday, March 25, 2011

Spring migration 2010 and 2011

It looks like the adult bird started it's spring migration in 2010 on March, 9, which is similar to the date of the onset of the spring migration of 2011. Although the starting point was  a bit different, the pace of movement is somewhat similar. Perhaps the earthquake is was just a coincidence. Whatever the reason, the bird did avoid the massive and tragic quake.

Wednesday, March 23, 2011

Migration started

After spending 4 days on the snowy east coast of Hokkaido (yes, up to 1.5 m of snow according to Japan Meteorological Agency Map), the adult eagle took off and headed North. Crossing to Sakhalin was done in the same place as last year. Interestingly,  now (21 March 2011), the eagle is on ice in the Tatar straight. Last year it was in the same spot at the same time.

Friday, March 11, 2011

Japan Earthquake, part 2

Just got the GPS data and cross-referenced it with the earthquake chronology. The data are very interesting.

9 March 2011, the eagle is at the top of a mountain ridge some 8 km SW from Ashbetsu town, Hokkaido. The fix is taken at noon, which is 2 am UTC. At 02:45:20 AM the global seismological network registers first earthquake of Hokkaido with magnitude  7.2 (source:
This transliterates into magnitude 3 tremor in some parts of Hokkaido (source Japan Meteorological Agency The bird takes off in a direction opposite to that of the earthquake, and the next fix comes on 10 March from the top of a small mountain ridge some 10 km east of Rumoi, a town on the west coast of Hokkaido. Direct line travel was 55 km.
During this time there were a number of earthquakes off the coast of Honshu, but the first one which was accompanied by a tremor of magnitude 3 on Hokkaido was reported on 15:32, i.e. after the fix. The bird was continuing to fly north-west, and the Doppler transmission (no GPS fix yet) was received from a mountain ridge some 15-20 km north of town Haboro. Direct line travel is 63 km.

On the attached picture: yellow line - gps track. White dots in close to the coast show latest doppler coordinates taken at 3 am UTC, that is roughly 2 hours before the main hit of 8.9 magnitude stroke (2011/03/11 05:46:24) off coast of Honshu.

So, can a bird predict an earthquake? Probably not, but certainly our Steller's Sea Eagle flew away from a modest tremor, and by the time the major hit came on 11 March, it was away from the zones where tremors occured. It is likely that the bird will continue to move. The general picture is that by moving away from first tremors the bird was farther away from the epicenter by the time the main quake occured. Perhaps birds are more observant to small signs of on-coming earthquakes?

Japan Earthquake and the Steller's Sea Eagle

Although our payers go out to the people of Japan who face the aftermath of the massive earthquake and tsunami, I was looking anxiously at the data  coming in from the adult eagle (the last we have on the air). The latest batch of the data came when the internet was flooded with scary images of the megaflood and huge amounts of damage to the east coast of Japan. The plot of the latest Doppler coordinates  show that at the eagle flew from the Furuno city area, Hokkaido, straight north-west, to the western coast of the island. The bird has never visited this coast before during the monitoring period, and so it seems a bit strange, since movements in this year have only taken it to areas that it has visited before (last year). Whether it was traveling before or immediately after the earthquake is not known at the moment, but is it evident that the bird has moved from an area that suffered a magnitude 4 tremor to an area where the magnitude was only 2. The picture shows the land tremor (red dots = 6, violet =7, epicenter marked with red cross) as was issued by the Japan Meteorological Office and location of underwater tremors from USGS real-time earthquakes. The bird's track is shown in white moving from the center of Hokkaido to the west coast of the Island. Note that the bird was flying away from from the epicenter (thick white line shows the direction to the epicenter on both pictures).