Tom’s Finch

On the last day of September, our son Mark found the first migrating white-crowned and white-throated sparrows behind the barn and guesthouse. He also pointed out a Lincoln’s sparrow he had discovered at the edge of the hedgerow bordering First Field.

I’m not an expert on the “little brown jobs,” as birders refer to the many look-alike sparrow species. While I’ve learned song, chipping, field, American tree, and white-throated sparrows because they are here for months either during the breeding or wintering seasons, I had never seen nor heard a Lincoln’s sparrow until Mark showed it to me.

At first I thought it was a song sparrow, and I wondered how many Lincoln’s I had dismissed over the years as song sparrows. They are both in the genus Melospiza, along with swamp sparrows, and the one Mark found even had the diagnostic dark breast spot of a song sparrow, although most Lincoln’s do not. But this sparrow was smaller than a song sparrow, had grayer head stripes, lighter streaking on its sides, a broad, buffy-colored chest band, and a white belly.

After that I looked more closely at the sparrows on First Field which was, at that time, a 37-acre goldenrod and aster meadow. On October 2 I was outside at 9:30 a.m. and, as I neared the field, birds flew up from the browning goldenrod including several Lincoln’s sparrows with a song sparrow.

Then began a burble of song at song sparrow pitch but with less structure. It was pure, bright bird music, described as warbling and wren-like by some observers. But when artist and naturalist John James Audubon first discovered it in Labrador in 1833, he wrote in his Ornithological Biography that “the sweet notes of this bird as they came thrilling on my sense, surpassing in vigour those of any American Finch with which I am acquainted, form[ed] a song which seemed a compound of those of the Canary and Wood-Lark of Europe.”

Audubon and his companions chased this new species from bush to bush, trying to shoot it for a type specimen until finally 19-year-old Maine native, Thomas Lincoln, “with his usual unerring aim,…cut short its career…I named it Tom’s finch, in honour of our friend Lincoln, who was a great favourite among us.”

The last time I saw Lincoln’s sparrows in First Field was the fifteenth of October when they still looked to me like song sparrows but sang their warbling song. According to The Birds of Pennsylvania by Gerald M. McWilliams and Daniel W. Brauning, most records for Lincoln’s sparrows here are from the first week in September to the fourth week in October, and banding records at Powdermill Nature Reserve record as many as 15 birds a day during the first and second weeks in October.

Lincoln’s sparrows breed from Alaska across Canada as far north as northern Quebec and Labrador in eastern Canada, south through the western mountain ranges in the United States, and from northern Minnesota to eastern Massachusetts. The closest known breeding range to Pennsylvania is in northern New York state, although there is one record of a singing Lincoln’s sparrow on July 24, 1988, at 2300 feet in elevation at Rickett’s Glen State Park in Luzerne County.

Lincoln’s sparrows east of the Mississippi River usually winter from northwestern South Carolina, Georgia and Alabama to central Florida. Those west of the Mississippi River can migrate sometimes as far south as Costa Rica and Panama, making them adventurous migrants that head farther south than most sparrows, but no matter where they go, they always use brushy, weedy areas close to shrubs both when they are migrating and on their wintering grounds.

They also migrate through Pennsylvania during the spring, usually in May, but they move through the commonwealth more quickly than during their dawdling fall migration, and as many as 30 have been counted at Presque Isle State Park near Erie.

In eastern North America, breeding Lincoln’s sparrows are birds of boreal shrub lands that are sometimes boggy. Because they are often bullied by song sparrows, according to J. Murray Speirs and Doris Huestis Speirs, who studied them from 1955 to 1957 near the north shore of Lake Superior in the Thunder Bay District of Canada, Lincoln’s sparrows could only breed in the same area as their congeners “by dint of persistent passive resistance: they always fled and returned later by stealth.”

The Speirs observed Lincoln’s sparrows on trout hatchery grounds from their car because “with black flies, ‘no-see-ums,’ and mosquitoes active and plentiful, a parked and closed car seemed the only livable observation point in the country.”

They and other researchers have found Lincoln’s sparrows difficult to study because of their skulking, secretive nature. Still, the Speirs had no trouble seeing the males singing from elevated perches, defending their acre of territory from other Lincoln’s sparrows by singing, buzzing calls and wing-flapping, and breeding by pouncing on their mates, usually after the females encouraged them. The Speirs’ pair was less secretive than most Lincoln’s sparrows where mating was concerned, copulating on the ground, on brush piles, on a picnic table, even on a sign, and one morning, while the female was nest-building, seven times between 8:00 and 10:13.

But the Speirs couldn’t find that nest even though they watched where the female landed, first with grass and later food in her bill. Finally, with another couple, they crawled around on their hands and knees and still couldn’t locate it. Then, after supper on June 24, 1956, Neil Atkinson, a young school boy, “came puffing into our house, having run the mile from the nest site, to announce that he had succeeded in locating the nest. Immediately, we went back with him, and there the nest was, right where we had looked, but set well down into the ground under a pile of last year’s brush cuttings. It looked like a little black hole.”

They added that the Lincoln’s sparrows use “shrub growth less than 8 feet high for concealment and from which the male can sing, openings carpeted with grasses, heaths, or annuals less than 2 feet high in which they can forage, and a substratum of brush cuttings, grass clumps, or sphagnum that the nest may be sunk into.”

A female Lincoln’s sparrow digs out a small depression in the ground and using willow bark, grasses and dried sedges weaves a four inch by two inch nest, which she lines with a thick layer of thin, soft plant material. In it she lays three to five pale greenish to pinkish eggs specked and blotched with brown. She then incubates the eggs for 13 days.

The Speirs found it difficult to locate the nest because the female engages in what ornithologists refer to as the “rodent-run” when she leaves and returns to the nest after eating. Holding her wings against her body she lowers her head and breaks through a tunnel in the vegetation or later, during incubation, she flaps her wings and noisily breaks through vegetation especially if she is defending the nest from an intruder such as short-tailed weasels, shrews, or gray jays, all of which may prey on eggs or nestlings.

The male remains solicitous, mate-guarding her particularly during egg-laying because most studies on their breeding grounds have found twice to three times as many males as females so they are precious commodities.

He also pitches in to feed them as soon as the helpless, altricial young emerge from their shells, although mostly the female broods their helpless hatchlings for a portion of their early nesting period at one to five days of age. The Speirs’ sparrows were fed green caterpillars, small white moths, and young grasshoppers, but overall, adult Lincoln’s sparrows over a year consume both insects and small seeds in equal amounts.

The young Lincoln’s sparrows mature quickly and leave their nest at 10 to 11 days old, although they can’t fly yet and spend most of their time hiding under dense shrub cover, but they often sleep at night back in their nest for several days. They practice flying during the day by first hopping and wing-flapping to nearby branches, then gradually making short and then longer flights until they are able to fly well by 18 days of age.

Because Lincoln’s sparrows are difficult to observe on their boreal breeding grounds due to their secretive natures, much of their biology and ecology are still unknown. Yet their numbers seem high during migration so they are in no danger of disappearing.

I look forward to seeing and hearing their singing this fall now that I know they visit our First Field. (See a YouTube video below that shows a singing Lincoln’s sparrow.) To me they are examples of the wonder of the natural world where I can always find something new even on familiar ground.