Sunday, April 26, 2015

The Private Life of a Sanderling, an Arctic Snowbird in Florida‏

Sanderling V4Y at Palm Island

We are surrounded by a profusion of amazing animal life of many types, yet the birds especially appeal to the human mind as expressions of beauty and mystery.  How many times have you gone to the beach and seen tiny birds running rapidly in the surf zone picking up food?  These sanderlings are common almost everywhere, yet how much do we know about them?  One way to study them is to band their legs so that they can be tracked visually.  So researchers have come up with a system of colored and/or marked bands which can be identified from a distance.  When I go to the beach I watch for banded birds and get a photograph of the band(s) if possible.  The markings can usually be identified on bandedbirds.org  and a history of the previous capture and re-sightings found.  

While at Palm Island, SW FL, I photographed a sanderling with a light green leg flag engraved with black ink as "V4Y."  This bird was first marked May 10, 2014, at Mispillion Harbor, Delaware, and subsequently re-sighted there four times between May 11-27.  The next sighting was mine 11 months later on April 26, 2015, so it is possible to recreate some of the remarkable migration pattern of this individual sanderling.  It seems to spend the winter in the Gulf of Mexico, probably most of the time on Palm Island and nearby Manasota Key.  In early May it migrates to Delaware Bay and eats as much as it can of horseshoe crab eggs and invertebrates to fuel its flight to the Arctic shores of Canada's Northwestern Territories where it will breed.  

The mere thought of such a tiny two ounce bird making this long journey is hard to fathom.  But even harder to understand is why.  What is the purpose of such a long and perilous migration?  It would appear that the advantages of breeding in an Arctic habitat that is suitable for only a very short time in summer, outweighs the dangers of the long migration.  Such a life strategy is subject to the impacts of changes in habitat or climate or food all along the migratory pathway.  But over long periods of time it has been successful and we hope it may continue to be so in the future.  Human help to protect  the links in the migratory chain will likely be necessary for future survival of such vulnerable species.  So next time you are at the beach and see those tiny birds running in the surf, give them some respect, and marvel at their life story.

Bill Dunson

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