In April, North America’s largest swallow, the Purple Martin, returns to New England to breed. Nesting is now underway, and here in the East takes place almost exclusively in man-made colonial nest boxes. Prior to 1900, woodpecker holes in snags were the preferred nesting sites, but now only Purple Martins in the West tend to seek them out (unlike Purple Martins in the East, they often are solitary nesters). Even though humans have provided housing which has increased their population, there is still considerable competition from European Starlings and House Sparrows.
When they are not raising a ruckus at their nests, the iridescent dark blue-purple male and duller female Purple Martins can be seen swooping and gliding in the air as they hunt their insect prey. If there is a cold, rainy spell in the spring or early summer it can reduce their insect food supply and they can suffer great losses.
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Although male Baltimore Orioles have been known to partake in nest building, usually it’s the female who selects the specific site within the male’s territory and builds the nest. Located at the tip of a slender branch, this pendulous nest provides its occupants with as much protection from predators as is possible.
The material with which the nest is started usually consists of flexible plant, animal or human-made fibers, and provides support. “Springy” fibers are then woven into the inner bowl and downy fibers are used to line the nest. The oriole usually brings only a single fiber at each visit, and works it into the nest with a complex series of bill-weaving techniques. The nest is completed in roughly one week.
Construction material includes hair (especially horsehair), twine or string, wool, synthetic fibers (one oriole nest was made entirely of cellophane), various types of plant fibers including grasses, milkweed stems and grapevine bark, cottonwood or willow seed “cotton,” milkweed seed plumes and feathers. Females have been observed flying more than a quarter of a mile in search of construction material. (Photo: Female Baltimore Oriole on her first day of nest-building)
YESTERDAY’S MYSTERY PHOTO: Once again, Naturally Curious readers outdid themselves with creative solutions to a Mystery Photo. If you want a thoroughly enjoyable 5 minutes of entertainment, read yesterday’s comments! I will let you know if this mystery is ever solved.
This is what a typical Wild Turkey’s nest looks like – anywhere from 4 to 17 eggs in a shallow depression in the ground. Sometimes, however, turkeys engage in a practice referred to as “egg dumping.” A hen turkey comes along and lays a few eggs in several other turkeys’ nests, in an effort to maximize the number of her offspring that will survive. Up to 26 eggs have been found in a single Wild Turkey nest. The hen turkey that built the nest doesn’t reject the additional eggs, but rather, welcomes them to her brood, incubates them and treats them as her own. All of the precocial chicks are out of the nest within 24 hours of hatching and follow the hen, who feeds them for a few days until they learn to find food on their own.
Eastern bluebirds are preparing for the first of the two or three broods they will raise this summer. Contrary to what those of us who clean out our bluebird boxes have been led to believe, Cornell Lab of Ornithology states that experiments show preferences for nesting boxes containing old nests. In a paired experimental design bluebirds chose boxes containing old nests in 38 of 41 cases in which boxes with old nests were paired with empty ones. Scientists conjecture that this may be because the old nests often contain wasp larvae, an easy source of food for the bluebirds.
Females build their nest over several days. Grasses and pine needles are gathered from the ground and delivered to the nest box. Fine grasses, horse hair and turkey feathers often provide the soft, innermost lining of the nest. While the male enters the box during the nest-building process, perhaps to inspect, he does not actively collect material or participate in the building of the nest. Once the 3 – 7 eggs are laid, the female spends the next two weeks or so incubating them. She then broods the young for about a week, and both parents provide them with food for up to three weeks after the young have fledged. (Thanks to Jeannie Killam and Terry Ross for photo op.)
Great Horned Owls are said to have the widest range of nest sites of any bird in North or South America. Like other owls and falcons, this raptor does not build its own nest, but rather relies heavily on abandoned stick nests of diurnal birds of prey. Red-tailed Hawk nests are often usurped, as well as those of Bald Eagles, crows, ravens and herons. Nests may be lined with shreds of bark, leaves, downy feathers from the owl’s breast, fur of prey and trampled pellets. In addition to bird nests, Great Horned Owls also raise their one to four nestlings (usually two) in tree cavities and snags, on cliffs, in deserted buildings, in squirrel nests and even on the ground.
The female Great Horned Owl does all the incubating; the male delivers prey to her at intervals throughout the night. These early nesters have incubated eggs successfully when outside temperatures have been as low as -27°F. Hopefully warmer temperatures will welcome the newly hatched owlets in about a month. (photo: mostly hidden Great Horned Owl in Great Blue Heron nest)
White-winged Crossbills inhabit the boreal forests of northern New England, the southern edge of their breeding grounds. This species, as well as Red Crossbills, are named for their bill which is supremely adapted to extracting seeds from conifer cones. Crossbills use their crossed bills to wedge open cone scales, after which they lift the seeds free with their tongues. Individuals can eat up to 3,000 conifer seeds per day.
White-winged Crossbills are erratic nesters that have been found breeding every month of the year. The birds nest whenever the available food supply is sufficient for egg formation and is likely to remain sufficient for at least three weeks, during the more energy demanding nestling stage.
Three nesting periods have been observed, each corresponding to the ripening of cones from different conifer species. The first season occurs in early July, when the cones of Tamarack, or American Larch, and White Spruce mature. The second nesting period begins in January and February, when they rely mainly on White and Red Spruce cone crops and the third season is starting now, as Black Spruce cones begin to open up. (Photo: public domain, male White-winged Crossbill)