During the past week a familiar and ethereal song has been emanating from nearby woodlands. Male Hermit Thrushes have returned, as have their flute-like songs. These songs are made with a syrinx (not a larynx like humans have), an organ unique to birds. It is not much bigger than a raindrop in most birds and is extremely efficient, using nearly all the air that passes through it. (A human creates sound using only 2% of the air exhaled through the larynx.)
The syrinx is located where the trachea splits into two bronchial tubes. In songbirds, each side of the syrinx is independently controlled, allowing birds to produce two unrelated pitches (one from each half of its syrinx) simultaneously. Hermit Thrushes can produce rising and falling notes at the same time, creating the melodious and haunting song that greets our ears early in the spring. This renowned songster can be heard at https://www.allaboutbirds.org/guide/Hermit_Thrush/sounds
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The pollinated and fertilized white flowers of Red Elderberry (Sambucus racemosa) have recently developed into the red fruit for which this plant is named. Many people are familiar with its relative, Common Elderberry (S. canadensis), which produces dark purple fruit that is used to make jams, jellies, pies and elderberry wine. While Red Elderberry fruit can be used to make all of these, its raw berries are toxic. Red Elderberry’s popularity is greatest with pollinators, birds and four-footed mammals.
The cyanide-producing toxins in its flowers, (raw) fruit, stems, bark, leaves and roots do not seem to discourage wildlife’s attraction to Red Elderberry. The odor of its flowers, its nectar, and its highly nutritious pollen attract many ants, bees, wasps and flies. At least 50 species of songbirds eat the bright red fruits, including red-eyed vireos, ruffed grouse, song sparrows, gray catbirds, brown thrashers, and thrushes. Squirrels, mice, raccoons, and black bears also eat the fruit. Porcupines, mice and snowshoe hares eat the buds and bark in winter. The foliage is usually avoided by herbivores, although white-tailed deer and moose browse on it occasionally.
The Hermit Thrush is often one of the last thrushes to leave its breeding grounds in the fall — peak migration is between the end of September and the middle of October. High pressure, clear skies and wind from the north usually produce many sightings of this bird at this time of year. Unlike many other species of thrushes that winter in Central or South America, the Hermit Thrush is not a long distance migrator, and does not cross the Gulf of Mexico. Approximately one-third of all migratory flights end after only two to three hours of flight. Typically it makes several two-to-six-day stopovers to refuel before reaching its wintering grounds in southern U.S. and Mexico.
The Hermit Thrush is a nocturnal migrant, often departing roughly half an hour after sunset (over half of departures occur within 60 minutes after sunset and none after midnight) with most flights ending about 40 minutes before sunrise (none later than 20 minutes before sunrise). (Flight information from Birds of North America Online)
Inadvertently, the person responsible for my being able to photograph a Saddleback Caterpillar was not mentioned in yesterday’s post. Many thanks to Rick Palumbo for his extraordinary help with this endeavor.