After arriving back in Vermont in May, Baltimore Orioles mate, build their nest (female only) near the tip of an outer branch of an isolated tree (discouraging predation), lay eggs and incubate them for about two weeks before they hatch.
After spending the next two weeks in the nest, most nestlings are ready to fledge. It is at this point that you can actually see the nestlings as they cling to the outside of their pendulous nest, or perch on its rim as they noisily await the arrival of a parent with an insect morsel. Upon fledging, they can fly, but not very far. The parents will continue to keep an eye on them and feed them during these vulnerable first two weeks out of the nest until they can fend for themselves. (Many thanks to Nina and Jerry Hickson for photo opportunity.) (Photo: Male (topmost bird), female and nestling Baltimore Oriole)
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.
Your eyes are not fooling you. A Cedar Waxwing is visiting a Baltimore Oriole nest. Why? If you had the choice between scouting the landscape for an odd board here and there with which to build your house, or going to a deteriorating, abandoned house and helping yourself to a goldmine of available lumber, which would you choose? The oriole nestlings have fledged — their nest has served its purpose. It’s highly unlikely that the parents would ever use the nest again. Waxwings, which are relatively late nesters, discovered the abandoned nest and are taking advantage of the oriole’s (female builds nest) hours of collecting raw materials. Fiber by fiber a pair of Cedar Waxwings pulled this nest apart and recycled what they removed.
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.