This week those of us in the Northeast have been inundated with dark-eyed juncos, often referred to as “snow birds” due to their presence in much of the U.S. only during the winter months. Although this member of the sparrow family breeds here and is found year-round in New England, over most of the eastern U.S. juncos appear as winter sets in and then retreat northward each spring. Many of the juncos that we are seeing now are transitory migrants on their way to Canada and the Arctic to their breeding grounds. They will remain there until next fall, when we will experience a similar influx. Research has found that males migrate earlier than females, and that females tend to migrate further south than males. The timing of this migration is regulated primarily by the lengthening spring days.
Common mergansers can be seen year round in northern New England, but in the spring their numbers peak around the first week in April, due to the large number of birds that wintered further south and are migrating to Canadian nesting grounds. These birds are fish eaters, known to consume at least 50 species which they easily grasp with their bill due to the sharp projections along its edges. Egg-laying is still a couple of months away, but coveted tree cavities where they nest are being scoped out. (female common merganser on left, male on right)
What happens to insects this time of year? A few remain active, such as snow fleas, and some, like monarch butterflies, migrate, but the vast majority of insects overwinter in New England. The insects that stay here are susceptible to freezing due to the fact that they cannot control the temperature of their body. Some insects, such as woolly bear caterpillars, can tolerate having ice form in their tissues, but most insects go into a state known as diapause. When the days start getting shorter, these insects reduce the water content of their body, as water freezes at a high temperature compared to other liquids, and replace it with glycerol, which acts like antifreeze, protecting them from freezing. (Due to technical problems which hopefully will be resolved soon, I am unable to include a photograph with this post. My sincere apologies.)
Possibly because of the importance of summer fruits in their diet, Cedar Waxwings (Bombycilla cedrorum) are late nesters, but by late August adults have begun their migration to the southern states and Central America. This year’s young are beginning this (roughly) 900-mile flight now, a month after their parents have left. You can often find waxwings feeding in crab apple and other fruit trees where they stop over during their flight to refuel. Juvenile birds lack the sleek look of adults — the red wax-like feather tips for which this bird is named have not developed, and the color of their plumage is much duller than that of the adults.
White-throated Sparrow (Zonotrichia albicollis) numbers are building in northern New England as they head towards the mid-October peak of their migration south. Even though they are no longer constantly singing their “Poor Sam Peabody-Peabody-Peabody” song, which allows quick identification, White-throated Sparrows’ white throats, striped crowns and yellow lores (the area between the eye and the bill) make them one of the easier sparrows to identify. Don’t be surprised if you see this bird with a tan, and not white, crown. There are two color forms, white-crowned and tan-crowned. Interestingly, an individual bird almost always mates with a bird of the opposite color form. Males of both color types prefer females with white stripes, but both kinds of females prefer tan-striped males.
Broad-winged Hawk chicks spend their first five or six weeks in the nest being fed small mammals, toads, nestling birds and a variety of invertebrates by their mother. They then fledge, but for the next two weeks these young birds continue to use the nest as a feeding (food is still being provided for them) and roosting site. At about seven weeks of age they begin capturing their own prey, and remain on their parents’ territory for the next month or two — just enough time to learn the ropes before migrating south for the winter, which they are doing right now (peak migration is mid-September).
Solitary Sandpipers (Tringa solitaria) nest in the boreal forests of Canada and Alaska (in the abandoned tree nests of several different song birds!), and winter in the tropics, from northern Mexico south through much of South America. Individuals started their nocturnal migration south in June, which is both inland as well as offshore. In the fall, some birds appear to fly southeast over New England towards the Atlantic Ocean, as if on direct course to South America, while others follow the eastern coastline. Although their migration over New England peaked in July, you can find them through mid-October on the shores of ponds, resting and feeding during their long flight. As their common and species names indicate, they migrate singly, not in flocks like most migrant sandpipers.
American Bitterns have returned to New England from their southern wintering grounds, and are announcing their presence with a unique song that Sibley describes as a “deep, gulping, pounding BLOONK-Adoonk” that they repeat over and over. These secret, well-camouflaged marsh birds are almost invisible as they slowly walk through marsh grasses. When they stand still and point their bill skyward, they are easily mistaken for the reeds they inhabit.
The Eastern Phoebe, a member of the flycatcher family, is one of the earliest nesting songbirds to return to New England after spending the winter in southeastern United States. It is easily identified from its perch, where it typically wags its tail up and down repeatedly while waiting for an insect to fly by. The Eastern Phoebe is the first bird ever banded in North America – in 1804 John James Audubon tied a small circle of silver thread around the legs of phoebe nestlings and documented their return in successive years.
Recently Common Loons have been seen on several Vermont lakes and ponds. Spring arrival on nesting lakes depends largely on the timing of ice-out. During migration, Common Loons have what are called “staging” areas — lakes as well as rivers, where many loons congregate as they proceed northward (southward in the fall). Reconnaissance flights are usually made from open water north to territorial waters to see if the ice is on its way out.
Great Blue Herons are returning to their breeding grounds in northern New England, where they typically nest in colonies. Unlike the nests of songbirds, heron nests are re-used year after year. While an individual heron does not usually choose the same nest every year, they usually return to the same colony. While some colonies are active for only a few years, some have been known to be active for over 70 years. Because nests can be located up to 100 feet high in a tree (typically a dead snag in the Northeast), you rarely have a bird’s eye view of nesting activity. However, if you go to Cornell’s new live great blue heron web cam site (http://www.allaboutbirds.org/page.aspx?pid=2433 ) you can see every movement made by the great blue herons currently nesting in Sapsucker Woods in Ithaca, NY.
Although named for the chestnut band, or ring, around its neck (barely discernible to most eyes) this diving duck does have a distinct white ring around its bill. Vermont and New Hampshire are on the southern edge of the ring-necked duck’s breeding range, so while they do breed here occasionally, we’re much more apt to see them during March and April, when they are migrating further north, and again in October and November when they’re headed to southern U.S. and central America to spend the winter. (male on left, female on right in photograph)