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

Saturday, November 14, 2009

Rankin Migration - 14 Nov. 2009

Having travelled about 6300 miles in 53 days (700 additional miles this week) and 6000 miles (970 additional miles this week) in 52 days, Blue and Red (respectively) reached the Equator this week and appear to be headed for wintering locations somewhere in the western South American.

East to west the birds are separated by the Andes with Blue having remained on the eastern side, while Red has used a more-or-less coastal route on the western side of the Andes. North to south, however, Blue is only 30 miles further south than is Red despite significant passage of time and distance.

As of the last update Red flew south from the Caribbean Sea on the Panamanian coast stopping briefly on the coast of the Gulf of Panama. It’s not unusual for peregrines to cross large bodies of water like to the Gulf of Mexico or in this case the Gulf of Panama over to Colombia…what is a little usual is the route that he took – he flew 275 miles south through the Gulf of Panama into the Pacific Ocean, then made a “U turn” and flew 150 miles back towards where he’d come from ultimately turning southward once again coming ashore in Colombia 106 miles later.
While it is possible that he found a boat or buoy on which to rest, the data indicate that he was airborne for 26 hours and covered more than 530 miles.

More next week.

Alastair

Friday, November 6, 2009

Rankin Migration - 06 Nov. 2009

Here's a synopsis of the entire migratory route for both birds, and below is one of their respective routes in Central America and northern South America.
Over the last week, Blue covered another 450 miles bringing his total to over 5550 miles. As most of the Rankin band returns have been from Brazil, I expected his route to continue south easterly. He has done the opposite and has headed west toward Bogotá and the eastern foothills of the Andes. The image below shows a GE version of a location on an escarpment over looking a river valley near Villanueva, Columbia where he spent 16 hours – it’s pretty easy to imagine the relative ease with which he could likely fly down and capture prey from that vantage point
… and this Panoramio image was embedded in GE 2.5 miles from his roost location – pretty nice habitat.
Red hugged the Costa Rican and Panamanian coastline on the Caribbean Sea fro an additional 425 miles for a total of nearly 5000 miles. His most recent data point shows that he has changed direction abruptly and has headed south bringing him a location near Picacho Mountain and within 10 miles of the Gulf of Panama.
The Panoramio image (below) was embedded in GE 0.5 miles from his roost location – pretty nice habitat too!
Alastair