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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