Birds : On the wings of southwest winds
April is an exciting month of great change in the natural world. It is a month generally characterized by strong and fast moving frontal systems, interspersed with varying lengths of mild, bucolic, emergent spring days. This was exactly the weather experienced on the Vineyard this past week. All of New England is enjoying a mild heat wave and birds are arriving both day and night, riding northward on the warm southerly air flow. Welcome conditions after the cold winter and spring. All life forms, perhaps particularly humans, are ready for warmer weather.
The primarily insectivorous birds that escaped the northern winter by heading south to winter in the Caribbean and Central America were also waiting for the warm front to move north and a large pulse of migrants surged north this past weekend. Many fairly common species that breed on the Vineyard returned this past week, some in considerable numbers. Pine warblers and chipping sparrows, both common nesting species with similar long trilling calls, are back. The longer more insect-like trill of the chipping sparrow and shorter more musical trill of the pine warbler are hard to miss Island-wide.
Almost annually for decades several reports of indigo buntings, a highly dimorphic species in which males are brilliantly colored, little blue (indigo) birds while the female is nondescript with a bluish tail, are reported during this week. No reports of this American goldfinch-sized shockingly dark blue bird have been made to date. If you have one (or more) of these birds, please let us know as it is exciting to know they are about.
Photo by E. Vernon Laux
The first reports of indigo buntings invariably occur after the passage of a frontal system that comes across the Gulf of Mexico and keeps moving up the coast in early to mid April. These powerful systems have a counterclockwise flow creating easterly winds along the coast. Migrant birds get caught up in these strong frontal systems and coastal locations such as Martha's Vineyard will sometimes become the landfall for migrants that have been blown past their intended summer latitude.
The bird migration really picked up with the strong southwest airflow this past weekend. Just inland and on the North Shore of Massachusetts observers commented that it was the largest movement of common land birds many has ever seen in April. The bulk of the birds missed the Vineyard but what the island misses in quantity in the spring it generally makes up for in quality.
The following birds were detected in Oak Bluffs this past weekend. There were dozens of white-throated sparrows, many engaging in song and yellow-rumped warblers were seemingly everywhere. No fewer than four ruby-crowned kinglets were also heard and seen at the Head of the Lagoon. A charismatic woodpecker in the form of a yellow-bellied sapsucker was found drilling holes in a black willow. They drill holes then leave for a few hours returning later to drink the sap and eat any insects that were attracted to the sap flow. This seems a lot like fishing only the bait is sap and the fish are bugs.
With the warming trend, activity has quickened in the bird world. The beaches are active with piping plovers and oystercatchers. The American oystercatcher, with its outrageous coloring and noisy gregarious nature, is a favorite of any who are aware of them. These spectacular birds have been increasing significantly on the Vineyard for the past decade and can be seen almost anywhere there is a beach or salt marsh. From Menemsha in Chilmark, the Beach Road in Vineyard Haven or anywhere along the Beach Road between Oak Bluffs and Edgartown, these birds are present and waiting your inspection with a pair of binoculars.
A few snowy and great egrets have been found this past week at scattered Island locations. A couple of Bonaparte's and laughing gulls were seen off East Chop in Oak Bluffs. These birds were already in their alternate or breeding plumage with black heads. Northern gannets and both common and red-throated loons have been easy to find in considerable numbers in Nantucket Sound as well as along the south side of the Vineyard.
Loose flocks of sea ducks in uneven V-formation and lopsided lines have been impressive to watch near dawn off most headlands. Large numbers of black and surf scoters have been moving east through Vineyard and Nantucket Sounds both early and late in the day. Some flocks of scoters climb high in the air and head north right over the Upper Cape. Some seem to follow the Cape Cod Canal, but they refuse to fly under the bridge detouring up and over land.
Most raptors - ospreys, red-tailed hawks, northern harriers and Cooper's hawks - are already incubating eggs. Many land birds are also engaged in nesting and the dawn chorus from resident species gets louder and more impressive on a daily basis. With the weather finally taking a major turn for the better, everything, especially the birding, seems to be improving quickly.
This is a great time of year to look at birds, whether you have done it for years or are thinking of checking it out for the first time. There is no time like the present.
Until next week - keep your eyes to the sky!