Monday, November 23, 2009

Rankin Migration - 23 Nov.. 2009

Last week was a big week for BLUE, he flew over 1400 miles making his way through Colombia, Peru (briefly), Brazil and into Bolivia to a location 14 degrees south of the Equator (yellow line). He has now flown over 7700 miles. I’m wavering on last weeks suggestion that he will winter somewhere western South America…data collected from PTTs deployed in the Rankin Inlet study area by Earthspan (http://www.earthspan.org) in 1994 perhaps suggest an alternate wintering location. I have plotted two 1994 routes (PURPLE and GREEN) taken by females migrating to their respective wintering grounds in southern, coastal Brazil…the route that BLUE has taken this last week is remarkably similar to those taken by PURPLE and GREEN 15 years ago. Of interest too is the timing – BLUE and GREEN had almost identical timing while PURPLE was about 10 days ahead. The 1994 birds completed their respective migrations in the first week of December.

Distance-wise RED had a much more sedentary week in comparison to BLUE, and flew an additional 330 miles just crossing into Peru (total distance flown is now about 6400 miles). I’ve compared RED to two other birds (WHITE and ORANGE) currently being tracked by the Falcon Research Group (http://www.frg.org). For those who have visited the FRG site you’ll already be aware that WHITE and ORANGE spent the breeding season on Baffin Island and recently completed migrating, returning to their respective wintering areas in coastal Chile. Based on comparisons of route taken or timing, RED is either very close to reaching his wintering territory or alternately will make a final push southward. Other birds have shown a tendency to make longer daily flights in the last few days of migration, so I’ll go out on a limb and suggest that we’ll see BLUE much further south next week than he currently is.

Alastair

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