Birds

American oystercatchers
American oystercatchers are favorites of all who see them on Island beaches, mudflats, and marshes. Possessing the world's most colorful shucking knife for a beak, these birds can be seen with half-grown young at this time of year. Noisy and gregarious, they are often misidentified by visitors as "beach toucans" or puffins, much to the amusement of local birders. Photo by E. Vernon Laux

Seasonal shift

By E. Vernon Laux - June 28, 2007

The vagaries of weather on the Island continue to amaze even the most casual observer. Due to the influence of the surrounding waters and predominant winds, Island weather is different and is a large part of what makes it attractive to both bird species and humans, especially during the summer months. The summer heat and humidity has arrived, lovely weather for vacationers, summer visitors and residents alike. Area birdlife is fully engaged with breeding.

Staying much cooler in spring and summer, and conversely warmer in fall and winter, the Vineyard hosts plant species associated with more southern climes. It does not get as cold in winter and the growing season is longer, enabling some vegetation to grow here that wouldn't survive in suburban Boston, for instance. The same is true for bird species, and the Vineyard has populations of "southern" birds that would be unimaginable elsewhere in Massachusetts.

Several birds that are resident on the Vineyard reach the northern edge of their respective species limit here. They are rare elsewhere in the state. Barn owls, cyclic, yet basically common year-round residents, are well established on the Vineyard. This is the premiere location to find them in the state. Being at the fringe of their species' range they are subject to periodic large scale drops in population from which they fairly quickly recover.

Nantucket is beginning to have a small number nesting in boxes provided for them as well, but the species is accidental on Cape Cod and on islands in Boston Harbor. Occasionally a pair will be found nesting on a Boston Harbor island or in a barn on Cape Cod but they seem to disappear within a year or two and have never been able to establish a viable toehold. They are a species with a pan-tropical and semi-tropical distribution that really cannot survive the somewhat harsher winters found just north of the Island.

While some are sedentary and remain all winter, other members of the population undertake a southerly migration in fall. Every so often, however, an old-fashioned New England winter will dump lots of snow and bring biting prolonged cold to the Island, causing over-wintering owls great problems, and most expire from starvation. Returning migrant birds will then essentially re-colonize the Island in spring and the cycle repeats anew.

Range Expansion-North

Other species finding the northern edge of their range on the Vineyard include a large nocturnal bird that captures large moths in flight called a chuck-will's widow, a small nondescript greenish flycatcher called an Acadian flycatcher and an entire suite of birds that are very common here that are not further north. Whether global warming, increased bird feeding activity, or normal and natural range expansions, every year many southern species are not so gradually extending their respective ranges north. Carolina wren, northern mockingbird, northern cardinal, tufted titmouse, American oystercatcher and turkey vulture are just some of the species being recorded further north almost annually.

The past week the heat has produced a number of cuckoo sightings. These rather strange birds are about the size of a blue jay but are masters of camouflage and stealth. No hopping about in the branches or undergrowth for these greenish and gray birds. They move very slowly, nearly imperceptibly, remaining essentially invisible until they fly to a new location. They also are the only birds around with a fondness eating large hairy caterpillars. They perform a valuable service by eating all sorts of tent caterpillars. Both black-billed and yellow-billed cuckoos have been heard, but rarely seen, Island-wide.

Bob Shriber, a seasonal Aquinnah resident, spent last week fishing and birding around the Island. Highlights included an adult yellow-crowned night heron at Katama on June 20, a calling whip-poor-will near the Gay Head Cliffs at dawn on June 19 - the first one heard calling here in many years - and a couple of sooty shearwaters, right in close to shore with terns and gulls in Menemsha Bight. Not far offshore there are good numbers of shearwaters and lots of lingering northern fulmars. These tubenoses, found in offshore areas in the winter should be far to the north and breeding at this season. It is puzzling and troubling that so many should still be frequenting offshore waters at this season.

There continue to be many June reports of immature bald eagles flying around on the Vineyard. This is something that has noticeably increased in last decade and it seems that if it is late June then there must be at least a couple of young eagles exploring Island shores. The species as a whole has been slowly increasing and is now more common in the northeast than ever before. That said, it is still far from a daily occurrence to spot one of these large birds and it is always a delight and a highlight of any birding expedition.

Until next week - keep your eyes to the sky.

To contribute news about birding activities or sightings, call The Times Birdline, 508-693-6100, extension 33, or e-mail vernlaux@comcast.net.