SPRING on NANTUCKET is very DIFFERENT than on the MAINLAND.
For non-natives, it is a far cry from what we expe- rienced growing up in America with its profusion of flowers, leaves, insects, colorful birds and lots of all of them. Because Nantucket is 30 miles out to sea and surrounded by water, the climate is different.
The seawater surrounding the island takes much longer to heat than land mass, so the island is encom- passed by a “cold sink,” with waters much cooler than the land that restricts and retards emergent vegetation and its attendant insect life. When the sun does shine, it heats the island and this causes a large temperature difference between land and water – voila, instant fog.
Nantucket is superb in the spring for witnessing spectacular migrations of seabirds and waterbirds that winter on the ocean but breed far to the north in the Arctic. Staggering numbers of migrant Common and Red-throated Loons sometimes numbering in the thousands can be seen streaming east along the south shore or north off of Sconset, especially at dawn dur- ing both April and May. Huge numbers of sea ducks in the form of all three scoter species accompanied by Common Eiders fly by in long loose flocks often com- prised of thousands of birds. For birders from inland or the Midwest the spectacle is well worth the trip.
Northern Gannets, large white birds with black wingtips that look like a flying javelin with a six-foot wingspan, parade by in loose groups as they wing their way back to only a few breeding colonies in the Gaspé Peninsula in the Gulf of Saint Lawrence or to some rocky capes in Newfoundland. When they locate a school of fish they engage in epic bouts of plunge-div- ing after herring and mackerel that are amazing to watch, with spray flying and the birds ripping into the water from a great height in wave after wave. Once their dive takes them under water they fly with wings half open and can go as deep as 30 feet below the surface to grab a meal.
Proximity to the water creates microclimates on the island in the spring. The warmest areas are those that are sheltered from the persistent winds that are cold from any direction in the spring as they are traveling over cold seawater. Downtown, with its relatively-large buildings and trees, offers protection from these winds and allows the sun to do its thing, greening the vegetation literally a full month ahead of what is going on near the shorelines. A trip from downtown to Surfside, Cisco, Madaket or any of many beaches in May is enlightening. Leaving the greenery and spring-like feel of town and traveling a short way, it seems as if you have arrived back in winter.
Scrub oak and beach grass look as if they are still dormant, although a closer inspection will reveal greening and swelling buds and stem tips.
The effect this has on migrating land birds is that they try to stay away from the coast in the spring. The coast, especially the open ocean, is a dangerous place for all flycatchers, thrushes, warblers, vireos, orioles, buntings and sparrows as there is no place to land, nothing to eat or drink and danger from winged predators like gulls and falcon-like seabirds called jaegers that like nothing better than chasing and eating land birds that have strayed too far from the safety and security of the mainland.
The result of countless generations of birds migrating from north to south and back again, the species currently nesting here as well as those that pass through briefly, if at all, have evolved migratory routes and patterns that keep them away from the coast in the spring. Many species have evolved an elliptical route that takes them from South and Central America, up through the center of the United States from which they veer off both east and west to ancestral nesting grounds. Then during the southbound migration, many species fly out to the coast, where unlike in the spring, the now warm seawater moderates cold snaps and there is much more food available than inland. There are at least multiples of 10 times more birds visiting Nantucket during the fall than in the spring. Another reason for this is that bird populations are at their annual high with all the young birds – first-time migrants – in the mix.
American Oystercatchers, the bird with the most colorful shucking knife for a bill, a bright neon-orange color, called “Beach Toucans” by some shellfishermen, are nesting on island beaches, dunes and marshes right now. These large, noisy birds are adept at defending their young from avian predators in the form of Great Black-backed Gulls, American Crows and various raptors by fearlessly attacking them and using their impressive beak to harass and even rip feathers off the back of the offending birds.
Piping Plovers are also on nesting territory, either sitting on eggs or guarding newly-hatched young. The “nest” is merely a scrape in the sand in a very exposed area. The female does not begin incubating until the full set of four eggs is laid so that the young hatch synchronously. These tiny endangered plovers have become a lightning rod for controversy. The Endangered Species Act, a set of federal laws enacted to protect wildlife, has given agencies charged with protecting these birds power to act in their defense. This often means restricting beach access to four-wheel-drive vehicles for a time while the young plovers grow feathers to fly, much to the chagrin of humans who want unfettered access.
The sight but the even more powerful and haunting plaintive calls of the piping plover, an ethereal strident two-note whistle, on a cold New England beach in April or May make this species’ “value” incalculable. Sharing beach access with these fellow passengers on planet Earth is a pleasure to be enjoyed. The natural world deserves our protection. What is good for plovers is good for people as well.
This spring follows the winter of the Snowy Owl, a winter unlike any ever experienced with Nantucket at the epicenter with 33 individual Snowy Owls recorded on the Christmas Bird Count. The previous all-time high in the 80 years the count has been conducted was four Snowy Owls, so the question arises as to what happens next. Let’s look at what we know and attempt to tease out what we think may happen. We know that more Snowy Owls descended on Cape and Islands beaches beginning just after Thanksgiving than have ever graced our shores before.
It seemed to be raining Snowy Owls this past winter, like a crazed Harry Potter movie all about owls, and more people got to see these spectacular large Arctic-dwelling birds at various beaches and shorelines than since anyone has been paying attention. All of the birds that arrived were young birds engaged in attempting to survive their first winter. Since they are young and we know that Snowy Owls don’t attempt to breed until at least their third year, none of these birds will attempt to nest this year. Hence there is no need to fly back north to the tundra to find a suitable nesting area, a mate and a steady supply of lemmings.
No one really knows what the Snowy Owls are going to do. It is assumed most will start making their way north but some may very well take a leisurely and slow route back, which will bring them into contact with many species that they have never encountered and conversely have never encountered them. For the iconic Osprey, Nantucket’s “harbinger of spring,” the potential for conflict is very real.
Ospreys and owls really don’t like each other. This feud goes to their very DNA and they don’t need to be told they dislike each other. It is more than that. From the moment they break out of their eggs, Ospreys and owls are enemies. Great Horned Owls, the first bird to nest in North America each year, often courting and laying eggs in January and February, frequently use Osprey nests and poles for their own. When Ospreys return in the spring battles will erupt and often owls and Ospreys end up dead. This is very serious business for both species.
Several young Ospreys have wandered inland in the past couple of years fitted with transmitters and have been killed by Great Horned Owls. As this article was going to press there were still many Snowy Owls around, often using Osprey nest poles for a perch or hunting platform. That some fireworks between these two species will occur this spring seems inevitable. I hope it doesn’t break out into a war and that there are only a few incidents. At any rate any news on this front will be reported in the “Island Bird Sightings” column in The Inquirer and Mirror each week, so check it out. Until next time, keep your eyes to the sky. ///
Vern Laux is an ornithologist and resident naturalist for the Linda Loring Nature Foundation.
