Tuesday, August 28, 2012

Tracking bird migration - storms

Fletcher Smith with Akpik on breeding ground in the Canadian Arctic.
 The Raptor Center thinks all birds are interesting, not just raptors.  We are fascinated by recent information on the current fall migration route of  shorebirds called  Whimbrel.  Scientists at the Center for Conservation Biology (CCB) have

tracked 3 whimbrels off the east coast of Canada to the northern shore of South America via a previously unknown migration pathway over the open Atlantic Ocean. The route passed through the center of the vast Atlantic at one point passing 1,000 miles closer to Africa than to North
America and within 700 miles of the Cape Verde Islands. The bird with the longest flight flew
nonstop for 145 hours (6 days) covering a distance of 7,000 kilometers (4,355 miles). The three birds named Mackenzie, Taglu, and Akpik were originally marked by CCB and Canadian Wildlife Service staff on the breeding grounds along the Mackenzie River Delta in far western Canada (Mackenzie was fitted with a transmitter recovered from Machi, a bird that was shot on Guadeloupe in September of 2011). In mid-July the birds flew across the continent to the east coast of Canada and staged for approximately 2 weeks in the James Bay and the Gulf of St. Lawrence to build fat reserves. The birds then flew southeast, reaching the center of the Atlantic Ocean before turning south and making landfall in South America between Guyana and
Brazil. Although this portion of the Atlantic is used by true seabirds that roost on the water, it is
so isolated from shore that species such as whimbrel that cannot land on water were not believed
to reach it. The birds may receive some benefit from venturing this far out to sea in the form of
favorable tailwinds. Mackenzie averaged just under 30 miles per hour (48 kilometers per hour)
for the 6-day flight. The study has tracked whimbrels for more than 185,000 miles (300,000 kilometers)

since 2008.
Map of migration route for 3 whimbrels marked on breeding ground in western Canada.
Incredible flight through the open Atlantic was previously undocumented.

As of Aug 24 - One of the Whimbrels ("Pingo") that was satellite tagged this summer began migration on 18 August and has flown 2200 miles so far before hitting Tropical Storm Isaac (now Hurricane Isaac), with at least another 1000 miles to go to make landfall.

Pingo is entering the northeast quadrant of the storm, which seems to be how Whimbrels tackle these events, and it is expected (based on previous Whimbrel routes) to fly towards the center of the storm and then use the southwest quadrant (and the tailwinds that quadrant produces) as a boost towards landfall. Last fall "Hope" the Whimbrel took 27 hours and averaged 9mph flying through a similar sized storm, and then flew an average of 92mph for 1.5 hours out the back end towards land!

Sources of info: Center for Conservation Biology, Surfbirds.com (a Nova Scotia birding site), and a birding lists digest from Sialia.com

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