Friday, March 13, 2009

Satellite tag returned

Since 2006, one of our researchers, Rob Ronconi, has been heading up a research project tracking greater and sooty shearwaters. The migrations these bird undertake is phenomenal but not out of character for a number of widely roaming seabirds.

The small satellite transmitters are placed on the bird's back and are expected to fall off eventually when the bird moults. We, therefore, need to consider them disposable. However, this fall, one of satellite transmitters ended up in a small port in Brazil. It was on a bird that had been named Lavarello, a family name from Tristan da Cunha where greater shearwaters nest. We are not fully aware of all of the circumstances but it is suspected that the shearwater was caught in fishing gear and the transmitter was brought back to port by the fisherman, still transmitting its signal.

The tag has been located and we are hoping to have it shipped back to us. For a look at the tracks the birds took, go to The tracks for 2008, 2007 and 2006 are available. For the latter years you will need to look in the archives. The tracks from 2006 and 2008 were very different with some of the greater shearwaters travelling from the Bay of Fundy to South Africa and back to Tristan da Cunha. The two sooty shearwater tracks follow the coast of Europe and Africa in 2008. In 2007, the sooty shearwater tags did not work for long so data were limited for that year but unlike greater shearwaters, sooty shearwaters seem to fly to Europe before heading south, while greaters head across to Africa, back to South America and then back across the South Atlantic. There are many variations of this flight path, probably related to weather systems.

Rob plans to continue work this summer, including herring gulls. While herring gulls are not long migrators, their movements in the Bay of Fundy can be used to track surface feeding aggregations.

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