Of a Feather: Outstanding in their pasture

By BILL CHAISSON
By Bill Chaisson

I see or hear some birds near our cabin every day. The black-throated blue warbler is always in his patch of birch and maple saplings at the top of the hill. The chestnut-sided warblers haunt the hedgerows daily on both sides of the meadow. The phoebe is reliably somewhere near the barn.

But some other birds I encounter only once in a while. Earlier in the spring, I often heard the hermit thrush in the forest, but now he comes to the edge less frequently. The Blackburnian warbler seems to venture within earshot at random intervals. The pileated woodpecker swings through for a couple of days and then disappears for a week. I am guessing that we live at the edge of these birds’ territories, away from the center of their activities, which now must revolve around their nests.

But this morning I heard a bird song that I’ve never heard before. Not near the cabin and honestly not in my life. It was loud, and the singer gave voice three or four times in quick succession, then fell silent for about a minute, and then sang again a few times. The notes seemed all on or nearly on the same pitch. The rich whistle was drawn out for the first few notes, sped up a little on the next few, and then the notes came so quickly they became a rattling chime.

I went out looking for this vocalist and quickly found him because he was perched on a dead limb at the top of a maple. It was about 6 a.m. and overcast. The light was terrible. In the brief look I got, I saw a brown, sparrow-sized bird throwing back its head and belting out this single-pitched, varied-tempo song. He then flew off across the field to the trees on the far edge and began singing again.

He finally settled in the hedgerow between two meadows on a birch with a sparse crown. From behind I saw he had a lightly striped back and two wing bars. Circling around, I could see his clear beige breast, but in the poor light, very little else in the way of field marks.

What I could not see was his rufous cap and a pink bill, for this was a field sparrow (Spizella pusilla). I also could not make out his white eyering, but the song was unmistakable. The cadence has been compared to the rhythm of a ping pong ball coming to rest. It is also quite loud, and these sparrows very helpfully repeat it often to drum it into your memory.

And yet, why was this bird showing up in our meadow in the third week of June? I consulted the “Atlas of Breeding Birds in New Hampshire.” The entry for the field sparrow, written by Elizabeth C. Janeway, noted that this species tends to build its first nest of the season on or near the ground. It is often destroyed by bad weather or predation by blue jays, grackles, and even house wrens. In order to produce two broods in a season, a pair of field sparrows may build seven nests.

In a 1978 article in The Auk, Louis B. Best studied nesting success in Illinois and found that it to be only 11.2%. Snakes were the primary predators, accounting for 76% of failures. 11% of nests were parasitized by cowbirds, of which 63% were subsequently abandoned.

But upon having a nest ransacked, would they move to a new territory? As the breeding season advances, field sparrow pairs build a second nest higher than the first one, in a shrub but still within a few feet of the ground. So, while it has frequently been observed that field sparrows build a nest in a new location, I found no reference that stated they pulled up stakes and established a new territory. And yet, here he was.

I feel lucky that this male field sparrow picked our meadow to settle in, even if we were apparently a second choice. “The Birds of New Hampshire” describes the species as an “uncommon and local summer resident.” We are at the northern edge of its range here; it has never been seen in northern Coos County and only rarely north of the White Mountains. Before 1950 it was regarded as common from the Lakes Region south. Since then the size of the breeding population has declined as shrub-filled old fields have succeeded to forest across the state.

North American Breeding Bird Survey data show it declining in New Hampshire by 8.5% per year between 1966 and 2009. By the late 1990s daily numbers reported in the state dwindled to single digits.

In spite of its name, the field sparrow is not at home in agricultural fields. Rather it is found in old pastures that have advanced to a state of succession that includes shrubs and saplings coming up among the herbaceous vegetation. It is important that these old pastures be bordered by woodland because that is where the males like to perch when they sing: at the forest edge.

One of the field sparrow’s nicknames is the “field chippie,” It is in the same genus with the chipping sparrow (S. passerina), but the real chippie has a striking black line through the eye, a white line above the eye (below its rufous cap), and a black bill. The chipping sparrow’s song is a dry, rattle, with little change in rhythm, but like the field sparrow’s, each note is on or near the same pitch.

Field sparrow songs are known to vary among individual birds. My sense of pitch is not good enough to be sure, but I think my local bird seems to push the accelerating middle passage of his song up a half step.

I wish him every success with his next nest.

Bill Chaisson has been a birdwatcher from the age of 10. He is a former managing editor of the Eagle Times and now lives and works in the town of Wilmot. Contact him at [email protected].