A few tree swallows spent the winter here, but this week’s sightings are not in the same locations.

It is not often that the same species repeats at the top of this column but once again American oystercatchers are in the news as the Martha’s Vineyard Bird Club’s field trip on March 9.

A variety of seabirds have died and washed up on Vineyard beaches in the past few months. Many different people have noticed the above-average mortality rates, especially of common eiders. Scientists from the Seabird Ecological Assessment Network (SEANET), which is part of Tufts University's Cummings School of Veterinary Medicine, have discovered that the mortality is most likely due to starvation because of major parasite infestations, rather than avian flu or oil pollution.