Putting Fluff to Good Use

Warbling vireo using cottonwood fluff to build its nest in St. Louis, MO, 19 May 2019 (photo by Andy Reago & Chrissy McClarren via Wikimedia Commons)

12 May 2024

Eastern cottonwoods (Populus deltoides) rely on the wind for both pollination and seed dispersal. In the spring the male and female trees each produce an inflorescence.

The males produce catkins which drop off the tree when the pollen is gone. The females produce flowers whose seeds are embedded in fluff to carry them away on the wind.

Eastern cottonwood inflorescences: male and female (photos from Wikimedia Commons)

By the time the cottonwoods have gone to seed warbling vireos (Vireo gilvus) have returned to the trees on the shore of Lake Erie. Though the birds look nondescript their song is the sound that fills the air in the parking lot at Magee Marsh in May.

Yesterday at Presque Isle State Park we watched a warbling vireo building a nest in a cottonwood. The nest is a cup that hangs from the fork of two small branches. Both sexes help build it.

Warbling Vireo on nest, Ruby Mountains, Nevada

In s. Ontario [the region of Lake Erie], nest exteriors fashioned with insect and spider silk and cocoons, paper and string, and bits of birch bark; exterior walls composed of grasses, plant fibers, bark strips, plant down, hair, leaves, fine twigs, lichens, and rootlets. Linings were fine grasses, pine needles, plant fibers, rootlets, feathers, and leaves.

Birds of the World: Warbling vireo account

Warbling vireos put the fluff to good use.

p.s. Here’s a mnemonic to help you remember their song:

 The mnemonic of “If I see you, I will seize you, and I’ll squeeze you till you squirt!” is very useful in identifying and remembering this bird’s song.

While easily heard, the Warbling Vireo can be difficult to spot. They tend to perch themselves high in treetops. When they are seen, this common bird is often described as “nondescript”.

— from Indiana Audubon description of warbling vireo

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