Changing Spring Skies
Arrivals and departures of our avian friends
by: Virginia Andrews
Spring, the ancient philosophers tell us, is neither one thing nor the other, but contains elements of both winter and summer. Nowhere is this more evident than in our island birdlife.
Birds that have been here all winter begin to get restless. Birds wintering in more tropical zones, with Nantucket their summer destination, head north. Year-round residents shift into breeding mode. They are all in a race to secure the best nesting territory, hoping to ensure survival for their offspring.
Actual departure dates are a bit unpredictable. Birds do not read bird books. They often confound both statistics and ornithologists’ expectations. For example, Snowy Owls usually leave by the beginning of April. But in one exceptional year one lingered at Great Point until July 12. This is what keeps us interested.
Sea ducks are among the earliest to leave. Harlequin Ducks, if they have found mates, usually depart for the far north in mid-March. Common Eiders also leave early. They deal with still un-melted terrain by plucking their own breast feathers to make their nests, sheltering eggs and young. Although a handful sometimes remains in our area, the vast numbers of them will be gone by the end of March. Long-tailed Ducks, unusual in that they molt in three stages and almost reverse plumage color, use both coastal and interior areas. Alcids such as Razorbills also take off at the end of March. As inland lakes thaw in the north, Common Loons leave the salt and head back to fresh water.
Other sea and pond ducks begin showing signs of migratory restlessness during April. There is a good deal of competition. Raucous calls, head-bobbing, racing, splashing, dunking and just generally showing off are behaviors which some birders tactfully refer to as just “getting feisty.” Some form flocks or join others before committing to the actual trip.
All winter the ocean has been peppered with scoters: Surf, White-winged and Black. They usually leave by early May, although flocks may still be seen off the Sconset Bluff later. Their thin, high-pitched keening as they gather in rafts is an unearthly sound, thought by some to have given rise to the legend of the Tuckernuck Yo-ho.
Greater and Lesser Scaup, Common Goldeneye, Bufflehead, Canvasbacks, Redheads, Coots, Ring-necked Ducks and American Wigeon also begin to forsake the ponds and marshes where they fed all winter, heading north and west.
The Atlantic Brant, a small salt-water goose for which Brant Point, with its iconic lighthouse, was named, is on the same schedule. Wintering in bays and estuaries along the New England coast, they depend almost exclusively on eelgrass for food. When a virus killed eelgrass beds in Nantucket Harbor in the 1930s, the Brant departed and were gone for more than 70 years. Now they are a delightful, annual winter presence. But greater numbers are more often found in Madaket Harbor, where eelgrass is less compromised. Those we see here nest along Arctic coasts from the Foxe Basin to the western shores of Baffin Island. They have a long way to go.
Beginning to depart a bit later are Great Blue Herons, many of which have spent the winter. Occasionally one or two may stick around. In the thickets, Juncos and White-throated Sparrows melt away as spring progresses.
Meanwhile, arriving from the south, birds are sneaking back to places where they raised young successfully the previous year. One of the first to return is the nearly invisible Piping Plover. Again, this is a species that doesn’t read the books which say it arrives in the first week of March. Some come by the first of March, and every now and then one will spend the whole of a mild winter here. Tiny but hardy, they can endure the cold of a windswept spring beach equally with the broiling heat of the summer sun. Their nests a mere scrape, their main defense good camouflage, they can disappear like magic in a wrack line. But their piping calls earned them the scientific name melodus, and to some their sounds are the very essence of a wild shoreline. For the last several years March 23 has seen the first Osprey return like clockwork to his nest platform on Hither Creek, with his mate joining him the following day. Wintering in South America, it takes about two weeks of steady flying for these magnificent birds to reach their northern breeding territory. Dependent on fish for their sustenance, timing their egg-hatch to the herring run gives them hope of a head-start on strong, healthy offspring. But the young still have to fledge and learn to find and catch their own food, which can be tricky.
Also getting a head start are American Oystercatchers. One Nantucket-raised bird has spent the last two winters in Honduras. Others wait for spring at Cedar Key on Florida’s west coast. Nantucket’s nests are always a gamble, as storm tides can wipe out an early choice.
Arriving in early April, Tree Swallows start their balletic zig-zags in the air. Skimming over our ponds and marshes, they consume vast numbers of mosquitoes, mayflies, crane flies and other insects. Some will stay, finding our nest boxes suitable habitat, while others push on.
In the moors and grasslands, Eastern Towhees flood back, perch in their favorite bushes, and sing their “drink your teeeea” song, which is both territorial defense and advertisement. Grey Catbird monologues are not far behind.
Returning from Florida or the Gulf Coast, Great and Snowy Egrets are a delight as saltmarshes begin to green up. Nearly wiped out in the name of fashion, these graceful white waders finally recovered when laws protected them. They breed on Nantucket. Around the same time, brown, nondescript but noisy Willets will be commandeering sections of saltmarsh for their nests, flashing white wing-bars as they squabble.
In May, flocks of terns begin to circle over the beaches, trying to find just the right spots. Least and Common Terns are known as colonial nesters, banding together to defend their eggs and young from marauding predators. Like Piping Plovers, they often return to places where they raised young in previous years. But they also have to adapt to beach conditions, and storm surges can disrupt them. Protecting their nesting areas from human disturbance can be difficult as well.
By the end of May our six warbler species – Pine, Prairie, Yellow, Common Yellowthroat, American Redstart and Black-and-white – will have grabbed their summer quarters, with sometimes a bonus Northern Parula.
Meanwhile, resident birds have been picking territories, too. On our ponds, Mute Swans are large and conspicuous, snorting vehemently. They can become very aggressive, to the dismay of unwary kayakers.
Cardinals start sharing food. Mourning Doves coo and waddle after their mates, before dropping the untidy, haphazard bunch of sticks they call a nest on a branch. Although looking precarious, apparently it works for them. Chickadees pair up. They can be seen pounding on trees where a broken branch offers a potential cavity, or settle into a nest box. But on any fine day, the ubiquitous Song Sparrows sing a tune birders remember with the mnemonic “hip-hip-ho-ray, boys, spring is here.” ///
Ginger Andrews is a native Nantucketer, artist and birder, and leads bird walks for the Maria Mitchell Association. She writes the weekly “Island Bird Sightings” column for The Inquirer and Mirror, Nantucket’s newspaper since 1821.