Bird Profile

American Tree Sparrow

A tundra sparrow that arrives at northern feeders in late fall and leaves in March. The rusty cap, the bicolored bill and the single dark stickpin on a plain gray breast are the whole identification.

The American Tree Sparrow is the sparrow that shows up when the weather turns. Across the northern half of the United States it arrives in flocks in late fall, spends the winter working the ground under feeders and along weedy field edges, and is gone north again by early spring. If you live where it winters, it is one of the easiest sparrows you will ever learn.

The name is wrong and always has been. Early European settlers thought it resembled the Eurasian Tree Sparrow of home and named it accordingly. In fact it breeds in the low scrub and tussock tundra of the far north, well past treeline in places, and it nests on the ground.

For a feeder owner the practical facts are short: this bird eats seeds, feeds on the ground in flocks, ignores tube perches, and is only around in cold months. This profile covers separating it from the Chipping Sparrow and the rest of the winter sparrow crowd, what it eats, the setup that holds a flock, and how a tundra bird survives a Minnesota January.

How to identify an American Tree Sparrow#

Work through three marks in order and you are done.

First, the crown: solid rufous or rusty red, unstreaked, with a rusty line running back from the eye across an otherwise plain gray face. Second, the bill: dark on the upper mandible and clear yellow on the lower, a two-tone pattern no other common winter sparrow shows so cleanly. Third, the breast: plain gray, unstreaked, with a single dark smudge or spot in the center, often called the stickpin.

Supporting details include two crisp white wingbars, a rusty shoulder patch, warm buff on the flanks and a longish notched tail. The bird is slim, about 5.5 in (14 cm), and looks small-headed and long-tailed next to a Dark-eyed Junco in the same flock.

Confusion species

Range and feeder timing#

American Tree Sparrows breed across the arctic and subarctic: northern Alaska, the Yukon, the Northwest Territories, Nunavut, northern Quebec and Labrador, in willow and dwarf birch scrub near treeline. Almost nobody sees them there.

They winter across southern Canada and a broad band of the United States, roughly from the northern Great Plains and the upper Midwest east through the Great Lakes and the Northeast, and south to about Kansas, Missouri, Kentucky and Virginia. Numbers thin quickly south of that line, and in an average winter they are scarce in the Deep South and largely absent from the Southwest.

The timing is tight and predictable. First flocks reach the northern US in late October and November, numbers peak in the coldest months, and birds head north again in March, with the last stragglers gone by mid-April. In practice, if you feed in the Midwest or the Northeast, the tree sparrow season overlaps almost exactly with the junco season.

How many you get in a given winter varies. Harsh weather and deep snow push flocks farther south and concentrate them at feeders, so a yard can go from none to twenty birds after a storm. That pattern is worth planning for, as covered in storm and outage feeding.

What American Tree Sparrows eat#

In winter this is almost purely a seed eater. The natural diet is small seeds from grasses, sedges, ragweed, knotweed, goldenrod, pigweed and other weedy plants, gathered from the ground and directly from standing seed heads. Birds also take some berries and catkins.

On the breeding grounds the diet flips to insects: the short arctic summer supplies flies, beetles, wasps and caterpillars, and nestlings are fed almost entirely on animal food.

The energy math in winter is brutal. A bird this small loses heat fast, and Cornell's account notes that an American Tree Sparrow needs to take in roughly 30 percent of its body weight in food each day, plus a similar amount of water. A day without food in deep cold can be fatal. That is the honest argument for keeping a winter station stocked rather than intermittently topped up, discussed further in winter bird feeding.

The feeder setup that works#

Tree sparrows feed on the ground by strong preference. They will hop onto a low tray, but they will not queue at a tube port.

• Scatter seed on bare ground or use a ground feeder tray placed near, not under, dense cover.
• A low platform feeder keeps seed off wet soil and still suits them.
• White proso millet is the single best seed for this species and for the juncos that travel with them.
• Sunflower hearts are taken readily and leave no hulls to foul the ground.
• Cracked corn works in a mixed ground scatter, kept dry and offered in small amounts.
• Nyjer is taken occasionally where it spills below finch feeders, but it is not worth buying for them.

Do not clear every weed. A patch of standing goldenrod, ragweed or native grasses left through winter is a natural feeder that never needs filling, and tree sparrows will work it hard. The argument for leaving seed heads up is made in native plants for birds.

Behavior worth knowing#

Flocking. Winter birds move in loose flocks of a dozen to fifty, frequently mixed with juncos, and occasionally with White-crowned and White-throated Sparrows or goldfinches. They forage spread out, then flush together into cover and trickle back.

Seed head work. Tree sparrows will fly up into a standing weed stalk and beat or shake the seed head so seeds drop, then feed on what falls. Once you notice it, you will see it every winter in a weedy field.

Voice. The winter call is a thin, musical tseet, and flocks give a soft, distinctive teedle-eet that carries across a snowy field. The song, a few clear opening whistles running into a rapid warble, is mostly heard on the breeding grounds, though birds sometimes sing before they leave in March.

Snow roosting. Like several northern seed-eaters, tree sparrows shelter in dense cover and, at times, in snow cavities and under drifted vegetation on the coldest nights. Conifers and thickets in a yard are worth as much to them as food.

Nesting#

Nesting happens far from any feeder. The female builds a cup of grass, moss, bark and fine material lined with feathers or hair, placed on the ground or very low in a dwarf shrub, usually sheltered by a tussock or an overhanging plant.

Clutches typically hold 4 to 6 pale blue-green eggs with brown speckling. Incubation runs about 11 to 13 days and the young leave the nest quickly, around 8 to 10 days after hatching, which is normal for a ground-nesting bird in a very short arctic summer. One brood a year is the rule.

Population and conservation#

American Tree Sparrows are still numerous, but the long-term trend is downward, and multiple survey programs have flagged a substantial decline over recent decades. Be aware that trend estimates for arctic breeders are less precise than for southern species, because the breeding range is enormous and thinly surveyed; most of what we know comes from winter counts.

The concern most often raised is the breeding habitat itself. Shrub tundra is shifting as the Arctic warms, and a bird tied to that zone has nowhere farther north to go. Winter range shifts have also been reported, with the center of the wintering population moving northward over time.

At a yard level, the things you control are ordinary: clean feeders to limit disease spread in dense ground flocks, cover from cats and hawks, and consistent food in hard weather. Cleaning matters more than most people expect where birds feed on the ground, and the routine is in how to clean a feeder.

A tree sparrow setup that works#

1. Start scattering white millet on the ground or a low tray in late October, before the first flocks arrive.
2. Keep the scatter wide and thin, and refresh it daily in snow rather than piling seed up.
3. Leave weedy seed heads and native grasses standing through the winter.
4. Site the feeding patch within one short flight of a brush pile or hedge.
5. Keep water available and unfrozen if you can; a heated bath is used heavily in cold snaps.
6. Expect the flock to disappear in March. That is the birds going home, not the food failing.