August features southbound migration (Cape Cod) Vernon Laux

[Donna]

As the summer continues to sizzle on the Cape and Islands, birds of many kinds are heading south. Birds are in the air, both day and night, as they travel hundreds and even thousands of miles, evacuating the northern reaches of the Northern Hemisphere to escape the upcoming severity of fall and winter.

This past week, large numbers of land birds, migrants from the north woods, began to arrive in the region after nocturnal migratory flights. These included many northern waterthrushes, small streaky warblers that nest in prolific numbers across the boreal and tundra vastness of North America. While seemingly uncommon in Massachusetts, these hardy, freshwater loving, ground foraging warblers pass by in good numbers. They are remarkably common in Central America during the winter months — their chip notes emanating from virtually every patch of rain forest, jungle and mangrove woods. At least six individual northern waterthrushes were heard and seen on Nantucket Wednesday morning.

Other warblers, flycatchers, vireos and orioles are also on the move. In fact, any evening with clear skies through the end of the summer will have birds moving in the night. Evenings with light northwest winds will have lots of birds on the move, and a check of one's favorite patch of woods, stream or swamp the next morning should be worthwhile and exciting.

If you happen to be on Martha's Vineyard, the Gay Head Cliffs on the western tip of the island are always worth checking for birds in the morning. This beautiful spot, especially early in the morning before the crowds begin to make parking difficult and tour buses arrive, is where numbers of nocturnal migrants can be seen as they correct their flight paths and head back to the west and the mainland at dawn. While the birds are often hard to see — flying little shapes that don't want to stop and be seen — the experience in nonetheless mesmerizing.

Elsewhere at Cape and Islands beaches and tidal flats, shorebird numbers declined slightly this past week as many adult birds moved south and immature birds have mostly not yet arrived.

Shorebirds such as sandpipers and plovers have two peaks of migration in the region. Generally, the last week of July and first few days of August have peak numbers of southbound birds. These are all adult birds that have finished their nesting for the year and instinctively know to head south as soon as possible. Near the end of August, there is a second wave of migration when all the birds of the year, immature birds of many species and a few lingering adults, crowd Cape and Islands shores. Not only do the beaches and flats "load up" with shorebirds, but they are also accompanied by flocks of gulls and terns, often with some surprise visitors.

A trip to the beach, where time of day is not as important as it is in the woods and it is generally cooler, is a great way to go birding in this hottest of months. Birding the flats is all about the tide and weather. For birding at most beaches and tide flats, bad weather is a good thing. Many shorebirds will routinely over-fly many areas, and strong winds and rain will cause them to divert to the nearest landfall to ride out the storm. During and immediately after such weather is the time to get outside and see what has blown in.

Getting out in a boat, especially if one is able to go well south of Nantucket and the Vineyard, is another great way to see birds in August. Seabirds, those that spend their lives on the open ocean such as shearwaters, storm-petrels, jaegers and phalaropes are often abundant in offshore Vineyard waters. A trip offshore is a journey to another world, the marine environment where one might encounter all sorts of things that you will never see ashore. A selection of rather scarce sea turtles, Portuguese man-of-war, perhaps an increasingly rare and beautiful blue shark, an ocean sunfish, dolphins and whales, and a great variety of marine game fish are all possible sightings.

Given good weather, it is always worthwhile and exciting to journey out of sight of land. If one is able to journey all the way south to the edge of the continental shelf, some 100 miles south of Nantucket and the Vineyard, then one is truly fortunate to be in a place as different from inshore as can be. It's like taking a trip through time and space to a marine world as different from land as can be imagined.

Until next week — keep your eyes to the sky!

E. Vernon Laux's birding column appears every Saturday in the Cape Cod Times. Laux is the resident naturalist for the Linda Loring Nature Foundation on Nantucket.