Unusual birds, rare birds or birds which are very similar to more commonly seen birds can be difficult to identify. There were two such sightings this week.

As the sun began to set at the Martha’s Vineyard Agricultural Hall fair grounds Sunday evening, farmers began to haul their animals into waiting trailers, the last skillets were tossed in the air and only a few whirls of cotton candy remained shrouded in the golden August haze.

All signs pointed to the end of the 150th Martha’s Vineyard Agricultural Livestock Show and Fair but there were still a few awards to be handed out.

In our own language the world of plants is reflected in expressions such as “to put down roots” as one of passive and enduring immobility. In fact, Coastal Maine Botanical Gardens plant curator Bill Cullina says their very survival depends on their ability to wander. This secret, itinerant life of plants is largely hidden from our view as it happens over generations, in geologic time — a scale that slips outside the view of a human lifetime. But Mr. Cullina says it is no less evolved or functional than the other great migrations.