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Juncos and ragweed — Who knew?

  • Photo by Francie Von Mertens


Wednesday, December 27, 2017

The sun rises on goldfinches at our feeders. A dozen or so take turns on the small platform feeder but not always amicably.

Goldfinch numbers are picking up as winter settles in and wild food is harder to access.

The colder the night, the greater the birdfeeder activity when daylight returns. This week’s frigid overnight temperatures challenge survival and an early foraging start is essential to restore calories expended keeping small bodies warm during the longest nights of the year.

When temperatures plummet, chickadees, as one example, need to increase their caloric intake some 20 times their warm-weather needs.

Early-morning sun highlights what little gold remains from the goldfinch males’ breeding plumage. A yellow throat patch is easy to miss without binoculars.

The wisdom of evolution: a male’s muted winter plumage is hard for predators to see. The cardinal male’s brilliant year-round red remains a mystery. It must serve a purpose as cardinal populations are doing okay despite coloring that announces their presence to predators—as well as to females.

The next wave of feeder activity brings juncos with their usual white-throated sparrow tagalong. That tagalong species is a welcome first for our winter feeders and worth watching for.

The recent local Christmas Bird Count found 86 of these elegant sparrows, a count record by a long shot. Second highest occurrence was in 2000 when a record number of juncos was counted. It’s a record that might stand: 4,002 compared to this year’s second highest, 1,533.

Juncos appear to have recruited other fellow-sparrow travelers, white-throated included.

I've been asked a few times why juncos congregate in such high numbers along roadsides.

I haven't gotten beyond the obvious reason: Juncos are ground feeders, and bare ground these snowy days is found where it's laid bare by snowplows.

I give that answer, adding in sand and gravel grit that helps bird gizzards grind up hard matter like seeds.

A wood duck's gizzard grinding up acorns consumed whole illustrates the concept on a larger scale.

Over the years I've thought of adding sandbox grit to our feeder offerings but never got around to it. Perhaps this year.

I don't know to what extent road salt is the attraction. There are reports of songbirds, sparrows and finches included, pecking at salt blocks put out for livestock and deer. Winter finch flocks apparently are drawn to roadside salt, sometimes to the point of "fatal attraction"—run over by vehicles.

While grit is suggested now and again as an addition to a feeder area, salt never is. Popcorn, potato chips and the like are highly discouraged.

I did some research and have a few things to add about roadside juncos.

It turns out that ragweed is a major winter food for juncos. Ragweed is very common along roadsides. Along stretches of our road it's the most abundant "weed." I pull it up on our frontage as it's the major cause of late summer "hay fever."

Goldenrod gets the blame—in full showy bloom at the same time as eyes itch and noses run—but goldenrod pollen grains are large and heavy, transported by insects not wind.

One nondescript ragweed plant can cast over a million tiny pollen grains to the wind, no doubt whipped up by passing cars and trucks. It also can produce up to 500 seeds that are rich in protein and fat—the perfect diet for winter birds.

Smartweed, another roadside commoner prevalent along our road, is another significant seed source for juncos.

Oddly, the genus name for ragweed species is "Ambrosia."

Here's an explanation offered by the Hilton Pond Blog, South Carolina:

"Carolus Linnaeus—the early botanist and taxonomist who named new plants from specimens sent to him in Sweden—seemed unaware Common Ragweed is responsible for many fall allergies in America. In fact, he dubbed this sneeze-producing plant Ambrosia artemisiifolia, which to us hay fever victims is some sort of cruelty joke; in mythology, 'ambrosia' was the 'food of the gods' that granted immortality, and we know Common Ragweed is anything but."

Surely there is an interesting story why Linnaeus settled on "ambrosia."

The blog suggests the "rag" part of its common name stems from the need to pull out a rag (pre-dating store-bought handkerchiefs) to blow your nose when near the plant.

Perhaps.

On our busy ragweed-seeded road, I worry about the foraging energy expended. Cars are frequent. Juncos scatter up and return; scatter and return. Repeatedly.

In answer, we're generous these cold days with birdseed.

As always, and as I've written here in the past, the annual Christmas Bird Count was a pleasing day outdoors with fellow volunteers taking part in the largest, longest bird survey of all, nationwide and spreading.

The day ends at our latitude gathering around the woodstove, sharing results with other participants who surveyed other sections of our assigned count area.

As always: good company, human and avian.