Sparrows are scary. At least, that’s their reputation. People new to birding, or even not so new, often regard sparrows as sneaky and streaky, hard to see and hard to ID. But these fascinating birds become easier to recognize when we break them down by season and by groups.
Dividing sparrows up into groups is especially helpful. Some types are solitary and elusive, lurking in dense cover all the time. Others are more sociable, and flocks may gather in open habitats where they are easier to see. Looking at scientific names in your field guide is a good way to start separating out these groups; the first part of the name, the genus, gives you a handle on which species are closely related.
The fly in that ointment is the fact that many sparrows have been shifted into different genera (plural of genus) in recent years. American Tree Sparrow is a case in point. For many years, its scientific name was Spizella arborea. Recently it was moved into a genus by itself, and it’s now Spizelloides arborea. But it still has many traits in common with the genus Spizella, so that’s a good place to start.
Sparrows of the genus Spizella, like Chipping Sparrow and Field Sparrow, usually live in semi-open habitats — not in the middle of dense forest, not in wide-open grassy prairies. They’re not as shy and elusive as many sparrows, often perching up in the open. Sociable outside the breeding season, they gather in small flocks, and they have light, thin callnotes. All those points also apply to the American Tree Sparrow.
One of the most distinctive things about American Tree Sparrow is its northerly distribution. It breeds and winters farther north, on average, than any other native sparrow. (The Savannah Sparrow actually gets farther north in summer, but that adaptable bird also nests as far south as Mexico.) Contrary to what the Tree Sparrow’s name might suggest, most of its breeding range is north of treeline, on Arctic tundra. In winter, it is most numerous in the northern states and southern Canada, and it’s a rare visitor in the southernmost states.
For most of us, American Tree Sparrows are winter birds. They migrate late in fall and early in spring. South of Canada they’re scarce before November, and in some parts of the wintering range they don’t reach full numbers until December.
When they come to bird feeders in rural areas or open suburbs, we can study their markings, but elsewhere we often recognize them by general impressions. A small flock flits along the edge of a marsh or woodlot or field, all the birds looking pale and somewhat long-tailed. Watching from a distance, we’ll see them foraging on open ground or perching on tall weed stems, giving soft, musical calls. The ID is already clear, and their markings — as detailed in captions in this column — are just the icing on the cake.
What to look for
Size and shape. A slim, medium-sized sparrow with a relatively long tail.
Habitat and behavior. Found in open country in winter: fields, roadsides, edges of marshes or woods. Feeds on the ground or in standing weeds, usually in flocks, sometimes with juncos.
Head pattern. Crown and line behind eye reddish brown, against pale gray head.
Bill color. Bicolored, with black upper mandible and yellow lower mandible.
Underparts. Plain pale gray, usually with a dark central spot on chest.
Upperparts. Back striped with reddish brown, gray, and black. Two prominent white wing bars.
Superficially at least, the bird most similar to American Tree Sparrow is the Chipping Sparrow. Many people in the northern states and southern Canada get both species at their feeders but not at the same time: Chippings in summer, Trees in winter. But overlaps and strays mean that they can’t be identified solely by the calendar. Chipping Sparrows are a little smaller and shorter-tailed. Their bills are black in summer, a mix of pink and black in winter, but not neatly bicolored black and yellow. Their dark eyeline is narrow, black, and just as sharply defined in front of the eye as behind it, giving a different look to the face from that of the Tree Sparrow.
In some ways, Field Sparrow is very reminiscent of American Tree Sparrow. It’s similarly long-tailed, and it has the same general pattern of reddish brown cap and eyeline on a pale gray head. Its facial expression is different, however: the Field Sparrow has an incredibly blank, innocent face, as if it has never had a bad thought in its life. This look is created by the completely unmarked lores, between the eye and the bill (where the Tree Sparrow has at least some dark marking), and the whitish eye-ring, which is often quite conspicuous. The pink bill helps to complete the innocent look. The Field Sparrow also lacks the American Tree Sparrow’s dark chest spot.
In winter, we often see American Tree Sparrows in groups of about half a dozen or up to 15 or 20, but larger flocks may gather in regions where the species is common. Often, they associate with Dark-eyed Juncos, but they’re usually not with other sparrows. In open, weedy habitats along forest edges or roadsides, they’re typically easy to see, flying up to exposed perches when disturbed; in flight, their outer tail feathers may look pale. Their flocking habit, moderately long-tailed shape, and overall pale look may suggest this species even at a glance. With a closer look, the sharp wing markings, pale gray underparts, typical head pattern, and bicolored yellow-and-black bill are enough to confirm the ID.
For sparrow ID, it’s best to start with things like shape, behavior, and habitat, not field marks. On this Swamp Sparrow, it may be tempting to start with its reddish cap, like that of an American Tree Sparrow or Chipping Sparrow; but everything else about it is different. Swamp Sparrow is a chunky, heavy-bodied sparrow, usually solitary outside the nesting season, usually hiding in dense, low vegetation, revealing its presence with sharp, loud callnotes — in many ways, it’s the opposite of the Tree Sparrow. To follow up with field marks, we could note that the Swamp Sparrow lacks obvious white wing bars, and instead its wings are mostly solid rich reddish chestnut, enough to rule out every similar bird.
Singing a tune
When I was a kid, the radio in my parents’ house sometimes played a song called “On a Wonderful Day Like Today,” from a 1960s stage show. I haven’t heard it for years, but I remember one line in the lyrics. To describe how wonderful this day was, the song claimed, “Even the sparrows are singing a tune.”
That caught my attention. I didn’t care about musical theater, but I cared about sparrows, and I knew that some did sing very musical songs. I didn’t like the implication that tuneful sparrows would be unusual.
Although the Song Sparrow is named for being melodious, it’s not the best singer in the family. To my ear, American Tree Sparrow has one of the most beautiful songs, with clear sliding whistles and sweet warbles. Individuals vary, and each male Tree Sparrow sings just one song, often shared with many of its neighbors. It’s a characteristic sound of the Arctic in summer, but males start practicing in early spring before they head north, and attentive birders at temperate latitudes may catch their performance.
American Tree Sparrows are musical in winter, too: feeding flocks give a soft, clear call of two or three syllables. It’s often written as teel-wit or teedle-eet, but I hear it as Marguerite — in honor of A. Marguerite Baumgartner, the scientist who made the first studies of this species in the 1930s.