Tracking polar bears in the Beaufort Sea: August map

Here is the follow-up I promised to my post on the July track map for polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice. See that post for methods and other background on this topic, and some track maps from 2012.

The track map for August was posted on the USGS website on September 4th and is copied here below (Figure 1). The ice moved a bit further offshore during August but not nearly as far as it did in 2012. The ten bears from July were down to eight – their collars might have stopped working or fallen off (most likely), they might have left the area entirely (also possible) or they might have died (the researchers don’t say which).

 Figure 1. “Movements of 8 satellite-tagged polar bears for the month of August, 2013. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 8 of these bears have satellite collar transmitters [i.e., all are females]. Polar bear satellite telemetry data are shown with Ice Analysis charts from 26 August, 2013. Ice Analysis charts are made available by the National Ice Center. The land cover is made available by Natural Earth. Click on the above image to enlarge.”[Note that the dots with the polar bear icons are the end points (end August), while the other end of the string is their position in early August. The yellow dot is behind the purple dot, on shore; two of the bears present in July (see Fig. 2 below) are no longer being tracked - their collars might have stopped working or fallen off (most likely), they might have left the area entirely (also possible) or they might have died. The researchers don’t say.]


Figure 1. “Movements of 8 satellite-tagged polar bears for the month of August, 2013. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 8 of these bears have satellite collar transmitters [i.e., all are females]. Polar bear satellite telemetry data are shown with Ice Analysis charts from 26 August, 2013. Ice Analysis charts are made available by the National Ice Center. The land cover is made available by Natural Earth. Click on the above image to enlarge.” [Note that the dots with the polar bear icons are the end points (end August), while the other end of the string is their position in early August. The yellow dot is behind the purple dot, on shore; two of the bears present in July (see Fig. 2 below) are no longer being tracked – their collars might have stopped working or fallen off (most likely), they might have left the area entirely (also possible) or they might have died. The researchers don’t say.]

So, of the eight polar bears still being followed by USGS researchers in August, three were on shore and five were on the ice. Only time will tell if the three females on shore are pregnant and preparing maternity dens for the winter, but this seems the likely reason they are not on the ice with the others.

I’ll post the track map for September when it is available in early October at the USGS website.

The map for July 2013 is below, for comparison:

Figure 2. Movements of 10 satellite-tagged polar bears for the month of July, 2013. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 10 of these bears have satellite collar transmitters. Polar bear satellite telemetry data are shown with Ice Analysis charts from 29 July, 2013. Ice Analysis charts are made available by the National Ice Center. The land cover is made available by Natural Earth [this is the original caption]. Click to enlarge.

Figure 2. Movements of 10 satellite-tagged polar bears for the month of July, 2013. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 10 of these bears have satellite collar transmitters. Polar bear satellite telemetry data are shown with Ice Analysis charts from 29 July, 2013. Ice Analysis charts are made available by the National Ice Center. The land cover is made available by Natural Earth [this is the original caption]. Click to enlarge.

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