Friday, March 21, 2014

Sanderling

Sanderlings are small, gray and white sandpipers with black bills, feet, and eyes. Another field mark is their black shoulders (hidden on the bird in the upper photo, but clearly visible in the three birds below).  They often chase waves on the beach. They run towards receding waves and away from incoming water. As the sand is exposed, the birds probe for food. They are also found in other wetlands, especially during migration.

Breeding in the far north Arctic of both hemispheres, in North America their winter range is extraordinary—they can be found all the way from southern coastal British Columbia and Massachusetts to southern Chile and Argentina, a span of some 100 degrees of latitude (MacWhirther et al. 2002). Sanderlings, nevertheless, are seldom numerous and populations are threatened by people developing and using sandy beaches.

On 19 February, Erika and I were surprised to see but one Sanderling on the Rockport, Texas, beach—but the next day, on South Padre Island, we found a flock of three birds. Wintering birds of both sexes vary in their degree of territorial defence. Birds sometimes defend beach-front territories. At other times, birds do not act territorially, resulting in small flocks of the birds feeding together. (See also my previous Sanderling post).

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