Northern Cardinal Nests: Safety in Numbers
This is the time of year to keep an eye out for bird nests that were hidden by leaves all summer. Their location can reveal more than one might guess. As with many bird species, the female Northern Cardinal does most of the nest-building herself, usually selecting a site that is in dense shrubbery, often in a tangle of vines. Frequently there are two broods, but rarely is a nest reused. Instead, a new nest is built for the second clutch of eggs, and it can intentionally be located quite close to the first nest.
The two pictured Cardinal nests were both built this year, only four feet apart in a grape vine-covered stand of Staghorn Sumac. Two different birds would not have nested so close to each other due to territoriality; thus, the same bird most likely built both nests. Ornithologists feel that the presence of old nests may function as protection against predation. They found that when they placed an empty Cardinal nest adjacent to a Cardinal nest containing plastic eggs, there was significantly less predation than with single Cardinal nests. (Thanks to Jody Crosby for photo opportunity.)
(NB: Even though most songbirds only use their nest once and then abandon it, one needs a federal permit to collect bird nests.)
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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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Common Grackles Nest-building
Common Grackles are hard to miss and hard to mistake for any other bird, with their yellow eyes, iridescent bronze or purple plumage and long, keel-shaped tails. Most of the spring migrants have reached their breeding grounds, and courtship, mating and nest-building are underway.
Because grackles begin reproduction so early in the season, conifers are the nesting site of choice due to the cover they provide. Females tend to choose the actual site for a nest, and in so doing can be quite fickle, often abandoning partially constructed nests and selecting alternative sites. They earn this right, as they’re usually doing all the construction work, although males have been observed with nesting materials, helping to build and repair nests.
Look for their 6-8”-diameter, large bulky nests near water, agricultural fields or near human habitation. They are usually built four to twenty feet above the ground. If you find a bird on the nest, it will most likely be an incubating female (slightly less glossy than male) – males not only do not have a brood patch and do not participate in incubating the eggs or brooding the young, but roughly half of the males desert their mates during this time. Those that do remain participate in the feeding of their young nestlings.
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Blue Mud Dauber Wasps Building Nests
Yesterday’s Mystery Photo showed evidence of a Blue Mud Dauber Wasp (Chalybion californicum) scraping the mud with its mandibles as well as the resulting ball of mud it had formed to use as building material for its nest. You can get a hint in this photograph of the iridescent blue wings that give this wasp its common name.
Mud dauber is a common name for solitary wasps that make individual nests for their eggs/brood with mud. There are many species of mud daubers, but most are between one and one-and-a-half inches long, black or metallic blue, and typically have a narrowing, or “thread-waist,” between their thorax and abdomen.
Most species of mud daubers, after making a small (1/4” diameter) tube nest out of mud or refurbishing an old nest, leave to forage for spiders. Once a spider has been located, the wasp stings and paralyzes it, but does not kill it (so as to prolong decomposition), carries it back to its nest, and repeats this process over and over until the nest is stuffed with living prey. The wasp then lays an egg in this mass of spiders and seals the nest with mud. The egg hatches and the wasp larva consumes the spiders as it grows. After pupating in the fall, the adult wasp emerges in the spring, mates and the cycle continues.
The reason that the ball of mud that the Blue Mud Dauber had formed was not taken back to the nest site as building material appears to be a small rootlet which anchors the ball to the ground, preventing the wasp from removing it.
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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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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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.
Mystery Photo: Eastern Cottontail Rabbit Nest
There were some extraordinarily creative guesses for this Mystery Photo, with several correct ones that identified the cottontail rabbit nest pictured yesterday. Two species of cottontails can be found in New England – the common Eastern Cottontail Rabbit and the increasingly scarce New England Cottontail Rabbit. Although the two species are very difficult to tell apart, young New England Cottontails usually have a black spot between their ears and never a white spot, which makes this nest that of an Eastern Cottontail. The female rabbit digs a nest hole about four inches deep and up to eight inches long, usually in grass or thickets where it is well concealed. She lines it with grass and fur plucked from her body. After her 3 – 9 young are born, she covers the nest with her fur and dry grasses and leaves the are in order not to draw attention to the nest. She returns at night to feed the young, squatting over the nest while her young reach up to nurse. Unlike hares, rabbits are born blind with only a sparse covering of hair and remain in the nest from three to five weeks, when the white blaze on their forehead starts to disappear. Snowshoe hares are born with eyes open, fully furred and disperse from the nest soon after birth. (Thanks to Noreen Anderson for photo.)
Spotted Sandpiper Role Reversal
Spotted Sandpipers are a relatively easy shorebird to identify, with their spotted breasts, their constant body-bobbing/teetering and the stiff beat of their wings. Although they are a shorebird, they can be found near freshwater ponds and streams throughout North America. Spotted Sandpipers differ from most birds in that the male and female roles are completely reversed when it comes to breeding – from courtship to parental care. The females establish and defend their territory, often arriving on nesting grounds before the males. Females court the males, performing display flights as well as strutting displays on the ground. Males, usually less aggressive and smaller in size, do the lion’s share of incubating the eggs and brooding the young chicks.
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.
Snapping Turtles Laying Eggs
It’s that time of year again, when female aquatic turtles, including Snapping Turtles, are leaving their ponds to lay eggs. You are looking between the front and hind legs of a Snapping Turtle in this picture. The 30 to 40 eggs she’ll probably lay look like ping pong balls, only slightly smaller. As each egg is laid, she moves her front foot back to meet the egg, in what looks like an effort to ease it gently down into the pile of eggs below. When finished, she will bury the eggs and return to her pond. In three or four months, the eggs will hatch, and usually the young turtles emerge and head for the nearest pond (sometimes they overwinter underground). The sex of the turtle that hatches from each egg is determined by the temperature the egg was while it was incubating underground.
Male House Sparrows Rise to the Occasion
The House Sparrow’s (also known as English Sparrow) reputation leaves a bit to be desired. It is an introduced species which has thrived in North America to the point where it is considered a nuisance species and an agricultural pest. Its tendency to displace native birds such as Eastern Bluebirds and Tree Swallows from nest boxes does not endear it to many bird lovers. However, one has to acknowledge the fact that male House Sparrows are the exception rather than the rule when it comes to parenting. Males help choose the nest site, build the nest, incubate the eggs, brood and feed the nestlings and keep the nest clean by removing the nestlings’ fecal sacs. That’s more than can be said for some of our most admired species, such as male Ruby-throated Hummingbirds, which disappear shortly after copulation.
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