Marsh Wrens Nesting
More often heard than seen, the Marsh Wren has a distinctive song that quickly alerts you to the fact that they are nesting in the area. Sung by the male at dawn, dusk and sometimes throughout the night, the song is a rapid series of gurgling and buzzy trills. Though each note may only last for 1–2 seconds, they can sing continuously for up to 20 minutes, rarely repeating the same note. To hear their song go to https://www.allaboutbirds.org/guide/Marsh_Wren/sounds .
Even though their nests are plentiful (males build multiple nests) they are well hidden and difficult to detect in amongst the cattails and bulrushes where they are built. About 50% of males mate with two or more females and most males build at least six dummy nests for every female they mate with. (In some parts of their range males build an average of 22 nests.) Scientists aren’t sure why the males build so many dummy nests – perhaps as decoys for predators. They are built two to five feet above the ground and are about 7” tall and dome-shaped with an entrance hole in the upper half. Once the female has chosen one of the male’s nests or built her own, she lines it with strips of grass, sedge, cattail down, feathers, and rootlets.
Possibly as a result of intense competition for resources in the marsh environments in which they nest and raise young, Marsh Wrens routinely destroy the eggs of other birds, including other Marsh Wrens. (Note: Pictured active Marsh Wren nest was built in rushes, which are preferred over cattails later in the nesting season, when cattails have dried out.)
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Black-capped Chickadee Robbing Peter To Pay Paul
The time for nest-building has arrived for Black-capped Chickadees. They most often choose dead aspens and birches as nesting trees, and the punkier the wood the better so that the birds can easily excavate a cavity with their small beaks. While both male and female create the nest hole, the female builds the nest within the cavity by herself.
Most chickadee nests are used only once, and consist of coarse material such as moss for the foundation and finer, softer material such as the hair of rabbits or deer for the lining. The pictured chickadee is only a day or two away from laying eggs, for she is collecting shed fur from red fox kits (they grow three different coats on their way to maturity – gray, sand-colored and red) for the lining of her nest. She found a bonanza of nesting material on the dirt mound at the entrance of an active fox den, where the kits spend much of their time. (Thanks to Jim Block for photo op.)
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American Crows Building Nests
Congratulations to Robyn Deveney and Chris Wings, the first Naturally Curious readers who accurately suggested the Mystery Photo depicted the tracks of an American Crow collecting nesting material. As I approached the pictured area, I flushed two black birds who were soon cawing and flying overhead, with a stick protruding from one of their beaks.
Crows are one of the earliest passerine, or perching, birds to engage in nest-building and egg-laying. Crows tend to build new nests each year, seldom reusing a nest from a previous year. In New England both members of a pair are busy collecting nesting material such as sticks, bark strips, weeds and mud, in March. They bring this material back to the nest site, which is typically a conifer, and construct a bulky nest usually in the crotch of the tree or on a horizontal branch. It takes anywhere from one to two weeks for crows to complete a nest and up to six days to lay 2 – 6 eggs. Incubation typically begins in early April.
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Baltimore Orioles Building Nests
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.
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Eaglets Hatching
When eagle chicks hatch they are covered with light gray down and have brown eyes and pink legs. One parent, usually the female, spends most of the day in the nest with her young for the first three weeks, brooding and keeping them warm. The male provides most of the food during this time. After he delivers prey, she tears off small pieces and feeds them to the nestlings. The chicks gain weight rapidly – roughly ¼ pound a day – so that in three or four short weeks the young are nearly the size of an adult. Eaglets are roughly six weeks old before they are capable of tearing off food and feeding themselves, and at least eight weeks old before they leave the nest. (Note corn stalk that’s been incorporated into nest; photo: one-week-old eaglet & its mother)
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Bald Eagles Nesting
In the Northeast, Bald Eagles seek out the tallest trees around in which to build their nests. In certain locations in Alaska, coastal California and northern Canada where there are no trees, Bald Eagles will nest on the ground. When building a nest in a tree, eagles will usually build it in the top quarter of the tree, just below the crown, on limbs capable of supporting a large nest. Sticks from the ground are collected up to a mile away from the nest or are broken off of nearby trees. Additional materials are regularly added to the nest throughout the year, including daily additions during the breeding season (see photo).
Many live eagle cams can be found online (in Minnesota, one chick, one egg – http://mnbound.com/live-eagle-cam/ ; in Georgia, older nestlings: http://www.berry.edu/eaglecam/ ; in Pennsylvania, very young chicks: http://www.ustream.tv/decoraheagles ), giving the viewer a window into the incubation, birth and growth of these raptors. Depending on the location of the nest, one can see every stage of development, from eggs to hatchlings to all-but-fledged nestlings. In New England, eggs are soon to hatch, if they haven’t already. (Thanks to Marianne Blake for photo op.)
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Great Horned Owls Incubating Eggs
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)
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Black-capped Chickadees Starting to Build Nests
At least two to four weeks before one would expect to find a black-capped chickadee building a nest, one was busily collecting hairs shed by my chocolate lab yesterday. In addition to fur, chickadees line their nest with grass (not available yet here), down and moss (hard to come by with two feet of snow still on the ground). Chickadees are able to nest this early in part because they nest in cavities, which offer them protection from the elements. Not having bills strong enough to hammer out cavities in living trees, chickadees rely heavily on rotting stumps for nest sites — the wood in them is punky and easy to remove. Birch, poplar and sugar maple snags and stumps are preferred nesting trees. If you want to provide chickadees and other birds with nesting material, take advantage of the fact that dogs and cats are shedding now, and recycle their fur.
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Common Loons: Nest-building
Naturally Curious posts for the next four days will be devoted to Common Loons. They are nesting now, eggs are hatching, chicks are swimming, parents are feeding – life is good on ponds and lakes in the north woods, and I would love to share this magical time with you.
Both members of a pair of Common Loons contribute to nest-building in May or June. Their ground nest is often built on the sheltered side of an island, facing the mainland. It is usually within just a few feet of the water, eliminating the necessity for the loons to walk very far. (The position of their legs far back on their bodies is advantageous when it comes to diving and swimming, but makes walking very challenging.) Both male and female share the building of the nest, throwing submerged vegetation from the water onto the nest site or pulling it from the water while sitting on the nest. Material continues to be added to the nest throughout incubation. Nearly two feet in diameter, a nest can take a week or so to build. Successful nests (those that produce chicks) are often re-used from year to year.
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Baltimore Orioles Building Nests
Once the female Baltimore Oriole has selected her mate, she chooses a nesting site within his territory, often the tip of a slender outer tree branch, as it’s relatively inaccessible to predators. The female usually builds the nest by herself, taking 4 – 15 days to complete it. The first few fibers are wrapped loosely around branches. With apparently random poking, knots and tangles are created in these fibers. The female than adds more fibers, one at a time, to extend, close and line the nest. Somewhat miraculously, after days of laborious work, the nest takes on its gourd-like shape. Initially the weaving of fibers from plants such as grasses, milkweed stems or grapevine bark can be observed (horse hair, twine and synthetic fibers are also used). Towards the end, when the nest lining is added, the bird is hidden inside the nest and all that’s visible is the periodic bulging of the nest where she is applying softer material (often cottonwood or willow seed fluff, milkweed seed plumes or feathers) to cushion her eggs and nestlings.
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Bald Eagles Refurbishing Nests
Bald Eagles in New England are repairing and adding to their nests, even as snow and cold temperatures continue. They often reuse their nest year after year – a nest in Ohio was used 34 years before the tree blew down. Although most don’t reach the record-breaking dimensions an eagle nest in Florida did (9 1/2’ wide, 20’ deep, weighing almost 3 tons), they are impressive structures, averaging five feet and three feet deep. Typically eagles will choose one of the biggest trees in an area in which to build their nest. Because their nests will be used for many years to come, eagles often choose living trees (which will remain standing longer) in which to build them. The nest is usually located in the top quarter of a tree, just below the crown. Both male and female eagles collect sticks for the nest, either finding them on the ground or breaking them off nearby trees. In parts of Alaska and northern Canada where trees are scarce and short, eagles often nest on the ground.
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Red-eyed Vireo Nest
Abandoned bird nests are evident now that leaves have fallen off the trees. Consider the time and effort that goes into the construction of one of these single-use nurseries. Take the Red-eyed Vireo’s nest you see here lying on the forest floor. The female selects a nesting site — a time-consuming task, as the requirements are that it conceal the nest and provide shade for her young. (Too much sun will cause her to abandon the nest. One female who had selected a sunny spot was observed pulling nearby green foliage over her nest and fastening it in place with spider webs.) The female vireo then collects nesting material for the three layers of her nest: Exterior – tree bark, spider-egg cases, wasp-nest paper, lichen, green leaves and pine needles. (Nests exposed to sunlight may be decorated with light-colored tree bark such as birch bark.) Interior – bark strips and plant fibers. Inner lining – grasses, pine needles, plant fibers and animal hair. She then weaves these materials into a cup-shaped nest that is suspended from a forked branch by its rim. A trip for materials is made every 3 – 11 minutes and roughly twenty seconds is spent working each load into the nest structure. This intensive work takes the female vireo approximately five days – all accomplished without the aid of any hands or tools, and she only uses the result of all this work once. Fortunately, recyclers make good use of her efforts.
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Black-capped Chickadees Still Nest-building
Black-capped Chickadees tend to be early nesters, often as early as April, as they build their nest inside a cavity where it is sheltered from the cold. Chickadees rarely re-use a nest, so one might guess that this Black-capped Chickadee with nesting material in its beak in early July has a second brood on its way. However, it is unusual for Black-capped Chickadees to have a second brood of young after the first has fledged. If they lose the first brood, they sometimes will re-nest, but it’s more likely that this chickadee is just a late nester, as nest-building can and does occur up until mid-July. Both members of a pair excavate a cavity in a rotting tree, stump or post and then the female alone builds the nest inside the cavity. The foundation of the nest is usually made of coarse material such as moss. The lining consists of softer, finer material such as deer hair, rabbit fur, or in this case, an aging chocolate Labrador Retriever’s hair.
Red-shouldered Hawks Nesting
Male red-shouldered hawks put on an impressive courtship display for females. The male enacts a “sky dance” in which he soars while calling, then makes a series of steep dives toward the female, climbing back up in wide spirals after each descent, before finally rapidly diving to perch upon the female’s back. After copulation, the female lays her eggs in a nest which she has most likely used for several years. It is usually located below the canopy but more than halfway up a tree, generally in a crotch of the main trunk. Both male and female hawks build or refurbish the nest, adding fresh evergreen sprigs to it throughout the nesting period (eastern hemlock in pictured nest). Females do most of the incubating and brooding of the young, with the male providing food. The nestlings pictured are roughly two weeks old; in three or four weeks they will begin to climb out on branches away from the nest, in preparation for fledging.
Common Loons Nesting
Generally speaking, Common Loons return to northern New England from their coastal wintering waters sometime in April or May. Males and females pair up after they arrive at their ponds, and several weeks later they breed and build a new nest or renovate an old one, with the male choosing the actual nest site. Successful nests sites are often reused from year to year, especially if the male returns. Protection from wind, waves and predators is paramount. Because their hind legs are positioned so far back on their body, loons are awkward walkers, at best. Thus, they usually build their nest adjacent to water so that they can easily slip onto and off of it. The nest is constructed during the day by both adults and is made of vegetation that the loons collect close to the nest. A loon often sits on the nest while collecting material, stretching its head down into the water in order to retrieve vegetation which it then places on the nest. Two eggs are laid, usually between mid-May and early June. After being incubated by both parents, the eggs hatch in roughly 28 days. As this photograph indicates (egg just visible below loon’s body), material continues to be added to the nest during incubation.
Killdeer Nesting
This is the time of year when it pays to watch where you walk – there are a number of ground nesting birds, some of which, including killdeer, may choose your lawn or even your garden to build their simple “scrape” nest. Typically killdeer nest on the shoulders of roads, gravel roof tops, fields and gravel parking lots. The nest is very primitive, and there’s actually very little to it — killdeer scrape a slight depression in the ground, to which they often add bits of material, including white objects such as shells and bones. Their pigmented eggs are extremely well camouflaged. The young precocial killdeer chicks are on their feet and feeding themselves as soon as their down feathers dry. (Photo by Sadie Richards)
Red-shouldered Hawks Building and Refurbishing Nests
With winter temperatures still upon us, it can be challenging to find signs of spring in the hills of Vermont. However, subtle signs do exist if you know where to look! Notice the fresh greenery in this nest – it confirms that recent refurbishing has taken place by returning red-shouldered hawks. Roughly two feet in diameter, a red-shouldered hawk’s stick nest is lined with moss, lichen, bark and conifer sprigs. Other items that have been used as building material for these raptors include ears of corn, corncobs, corn husks, tissue paper, nests of songbirds, straw, mullein, leaves, twine, various deciduous tree leaves, entire plants, dried tent caterpillar webs and plastic grocery bags. The pictured nest will serve as a nursery for two to five red-shouldered hawk chicks in about a month’s time, and as the nesting season progresses, sprays of conifers such as the hemlock sprigs you see here will continue to be added.
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