For the Birds: Grassland Sparrows

This column is the second of three on grassland birds in Maine. In today’s column, we will take a look at three sparrows (Savannah, Vesper and Grasshopper) that require grasslands for nesting. In the next column, I’ll discuss the Upland Sandpiper and Eastern Meadowlark and end with some of the conservation challenges of these habitats.

The three sparrows in today’s column are more often heard then seen so learning to recognize them by song is the best way to find these somewhat shy birds.

The Savannah Sparrow is the most common of the three. Its breeding range covers most of the northern two-thirds of North America, extending into the arctic tundra. It is a migratory breeder in most parts of its range. During the winter, Savannah Sparrows withdraw to the southern tier of the United States and into much of Central America.

The species was named the Savannah Sparrow by Alexander Wilson, a contemporary of Audubon. Wilson collected a specimen in Savannah, Georgia and honored this charming southern city by naming a sparrow after it.

The song of the Savannah Sparrow has a distinctive buzzy quality. The song typically begins with a few short notes, then a buzzy trill and a final note or two of lower pitch. The song carries well, particularly the trill and final notes. A singing male can usually be seen singing from a grass stem or short shrub.

Visual identification of this species is straightforward. A Savannah Sparrow has a streaked breast like a Song Sparrow. The Savannah Sparrow’s streaks are less bold than those of a Song Sparrow and typically do not coalesce into a dot as in most Song Sparrows. The best field mark is the yellow line above the eye that is especially conspicuous in front of the eye.

During the breeding season, Savannah Sparrows mostly feed on insects. Outside of the breeding season, they switch to a diet of seeds they are able to find on the ground.

Like the Bobolinks discussed in the last column, a male Savannah Sparrow may have more than one female partner. The insect abundance in a grassland or meadow is abundant enough to allow a male to help feed two clutches of nestlings.

Vesper Sparrows have a broad distribution in North America, not quite rivaling the broad range of the Savannah Sparrow. Vesper Sparrows nest across the middle third of our continent and winter in the southern tier of states south into Mexico.

The song of the Vesper Sparrow has a distinctive beginning of two to four long clear notes followed by a downslur and then a series of flute-like trills, first rising in pitch and then falling. Vesper Sparrows sing throughout the day but continue to sing in the evening after most birds have ceased to sing. Those evening songs are the reason the bird is called the Vesper Sparrow.

The dependence of Vesper Sparrows on grassland habitats is doubly reflected in its scientific name, Pooecetes gramineus. Pooecetes means “grass dweller” and gramineus means “fond of grass”. In Maine, grasslands and blueberry barrens are the best places to find this sparrow.

The Vesper Sparrow is a rather large sparrow. These sparrows have a streaked breast and distinctive white outer tail feathers. Some of the wing coverts are rufous in color, giving rise to the older common name of Bay-winged Bunting.

We believe that Vesper Sparrows were rare in the east before European settlement. The clearing of forest for pastures allowed Vesper Sparrows to increase in eastern North America. The species is declining in the east now because of the reversion of so many farms to forest.

Grasshopper Sparrows are the least common of the three grassland sparrows. They breed broadly throughout the eastern two-thirds of the United States but are usually found in low numbers. Their populations have declined in many portions of their range because of the destruction of grasslands and prairies these birds require for nesting.

The common name of this species stems from its insect-like songs. Male Grasshopper Sparrows are unusual among sparrows in that they sing two distinctly different songs. Their Primary Song consists of one to three high-pitched notes followed by an insect-like trill. It can be described as tsick, tsick, tsurrrrrrr. This song is used to repel other males from its territory. A second song, the Sustained Song, consists of a more musical series of short buzzy notes given either from a perch or in flight to attract a female.

The pronounced flattened head, the large bill and upper orange breast make the Grasshopper Sparrow easy to identify once sighted.

[First published on June 28, 2008]