Cassin’s Sparrow

Known for their sweet trills and notes in their songs, the Cassin’s Sparrow is a secretive bird that practically disappears during some parts of the year. They are birds of arid shrub grasslands in the High Plains of North America, with significant populations also occurring in the south-western United States and northern Mexico. Breeding males sing a whistled melody while fluttering in mid-air, 20 feet high or more, above their territories. One naturalist wrote that the song had an “indescribable sweetness and pathos.”

About Cassin’s Sparrows

Occasionally, these birds are very common. However, most of the time they are irregular, with large numbers only appearing in an area after a period of good rains have turned the prairies green. They have nomadic tendencies and do not stick to any one region for too long. These habits have made flocks sometimes appear far outside their normal range, appearing on both the Pacific and Atlantic coasts. The records of their appearances are wide, fluctuating greatly depending on the weather and the climate.

Named by Samuel Washington Woodhouse in the honor of his dear friend John Cassin, these birds were only first observed in the middle of the 19th century. These birds are dramatic, graceful, and know how to put on a good show during the breeding seasons. Today, we will be delving into the lives of these prolific singers. We will be covering:

● Cassin’s Sparrow Photos, Color Pattern, Song
● Cassin’s Sparrow Size, Eating Behavior, Habitat
● Cassin’s Sparrow Range and Migration, Nesting


Cassin’s Sparrow Color Pattern

The breeding and nonbreeding plumages of adults are similar, with both maintaining mostly grayish-brown bodies and a plain face. Their faces are indistinct gray but hold traces of a buffy-gray supercilium or the “eyebrow”. Their crown is also gray. The bend of their wing is pale lemon, with the outermost feathers donning whitish tips. The less common rufous morphs are brighter overall with more rugous upperparts, wing and tail endings, and upper tail coverts. These birds are sexually monomorphic, meaning that adults of both sexes do not exhibit any differences in their appearances. Juveniles look similar to adults but have more buff in their feathers overall. They also have large amounts of dark brown streaking on their underparts, along with especially prominent streaks on their breast.

Description and Identification

Cassin’s Sparrows are furtive and can be hard to find as they forage at ground level in wide-open spaces so your best bet is to look and listen for them during spring and into summer when males sing their distinctive song and display in the sky. According to some birders, the far-carrying song is sometimes audible even when driving at highway speeds with windows rolled up! At other times of the year, a walk through brushy grasslands may flush a few Cassin’s, although they are just as likely to scamper away unseen.

Cassin’s Sparrow Song

The primary song of these birds is distinctive and dramatic, carrying over long distances. It is an exquisitely sweet and haunting song, comprising of two low and soft notes. Then a long, loud, and high trill follows, before finally ending with two shorter, descending notes. Males often sing this song while they fly directly upward to a height of 6.5–20 feet high.

They also have a complex song that is called the chitter flight song. It starts with a rapid series of “psit” notes that transition into a warbled chattering series. These are sometimes inside a series of primary songs, although this behavior is just them uttering the primary song after a series of chips, trills, and buzzy notes. This song is similar to the complex song of Bachman’s Sparrows. They sing this while they are on a perch or while they are in flight. There is also a whisper song that is also closely related to those of Bachman’s Sparrow, with males directing it towards their mates.

The chitter call is by males during courtship chases, by young chasing parents, or by overwintering birds when they are flushed from their shrubs. Highly agitated birds also give out these calls when they are overwintering. A high-pitch and up slurred “psit” is the most common call of the species, being given by males after they join their mates following a short separation. It can also be in response to female alarm calls. Young birds give a softer version of this call when begging their parents for food.

Cassin’s Sparrow Size

Cassin’s Sparrows are relatively large Sparrows that have a body length of 5.1 – 5.9 inches. They weigh about 0.6 – 0.7 ounces and have a wingspan of 7.9 inches. These Sparrows are sturdy and have a long, rounded tail, along with a flat forehead and a relatively large and long bill. These proportions make them larger than Chipping Sparrows, but smaller than Fox Sparrows.

Cassin’s Sparrow Behavior

These birds frequently hop on the ground, occasionally even running. They hop and clamber about twigs and branches within shrubs as well. They initially run when pursued but will direct flights that rarely go above 100 meters in height. When disturbed, they fly readily from one shrub to another but prefer to skulk through ground vegetation rather than fly. Like other Sparrows, they don’t swim or have any affinity with water. When giving out their flight song, they engage in “skylarking” behavior, meaning that males fly upwards while using trembling wing strokes.

Brewer’s Sparrows are also not aggressive outside of the breeding seasons. Males are responsible for claiming and defending a territory, while females generally secure the regions around the nest. When males spot rival males, they pursue their opponents by engaging in chases. Chasing and fleeing are associated with the establishment and maintenance of territories early in the breeding season. While it is most frequently the males and their male opponents who do this, females occasionally chase males that are not her mate if they venture too close to the nest site. Physical encounters are highly uncommon but may occur in extreme cases. During all other seasons, these birds form mixed-species flocks with other Sparrows.

Males arrive on breeding grounds several days before females and sing from visible perches to establish and defend breeding territories. In this display, a territorial male Cassin’s Sparrow flies up to a height of about 50 feet, singing the quiet first notes of his song. Then he floats down on stiff wings, with tail fanned and legs dangling, while completing the song. Their courtship timing varies regionally. In some parts of the range, pairs form in spring, when males establish territories and pursue females in flight. In other areas, pairs may be established before males begin to sing. Pairs sometimes chase each other in-flight around the territory, giving rapid buzzy calls. Males court females while perched in a shrub or on the ground, holding out and fluttering the wings, raising and spreading the tail, and bowing the head, in some cases giving buzzy calls.

After the nests are built, males remain in the immediate vicinity and take turns with their mates to incubate the eggs. Pair bonds are seemingly monogamous, but the duration of their bonds is not known.

Cassin’s Sparrow Diet

Cassin’s Sparrows eat seeds and insects year-round, though the diet consists mostly of seeds in winter. They feed mostly on the ground, moving along by hops, picking up seeds and insects from the ground, picking insects from low vegetation, or stripping seeds or flower buds from plants. During summer especially, they eat many different kinds of grasshoppers, as well as crickets, bugs, caterpillars, ants, bees, wasps, weevils, mantises, and spiders. Among the known plant seeds that they consume are chickweed, woodsorrel, sedge, switchgrass, and sorghum.

Cassin’s Sparrow Habitat

Cassin’s Sparrows inhabit dry grasslands with scattered shrubs, cactus, yucca, and small trees such as oak, acacia, mesquite, or hackberry throughout the year, avoiding areas of dense brush or shrubbery. They nest from sea level to about 7,000 feet elevation. They generally do not breed in cultivated fields, with the exception of alfalfa on occasion, and they tend to use native grasslands that are unburned and free from grazing animals. Throughout the northern parts of their range, Cassin’s Sparrows breed in grassy sandhills with sand sagebrush, rubber rabbitbrush, greasewood, yucca, and prickly pear. In South Texas, they occupy bunchgrass communities with spiny hackberry and prickly pear, while in West Texas they inhabit grasslands with scattered mesquite and juniper. In Arizona and New Mexico, Cassin’s frequent similar grassland habitats as well as desert flats with creosote bush. Migrants and wintering birds select similar habitats throughout the range.

Range and Migration

Although these birds are nomadic, most of their numbers are concentrated around the mid-Southwest of the United States and northern and central Mexico. Populations on the north-most regions of their range tend to move south during the winters, generally opting to winter along the western coasts of Mexico. Populations that breed in the southern-most regions of Texas and central Mexico tend to be permanent residents of their habitats that do not migrate in response to changes in the weather. All birds, however, move about in response to the availability of food sources.

Cassin’s Sparrow Lifecycle

Cassin’s Sparrows generally have a single brood in a year, but some populations in specific regions can have up to 2 broods. Each brood has an average clutch size of 3–5 white eggs, with mostly the females incubating the eggs, though further details of incubation are not well-known. When the eggs hatch, they are helpless with tufts of gray down. Their nestling period lasts for 7–9 days, but the exact age at which they first leave the nests is not well-known.


Their nests are set on or near the ground, rarely ever being placed more than 8 inches above the ground. Sites are generally located in a shrub or clump of grass. The construction of the nest is carried out entirely by females, who weave a loose cup out of grasses and weeds. The interiors are then lined with hair, fine grasses, and fine roots. The resulting proportions of the nest amount to be around 2.8 inches across and 2.2 inches deep.

Anatomy of a Cassin’s Sparrow

Cassin’s Sparrows are relatively large Sparrows that have a body length of 5.1–5.9 inches. They weigh about 0.6–0.7 ounces and have a wingspan of 7.9 inches. These Sparrows are sturdy and have a long, rounded tail, along with a flat forehead and a relatively large and long bill. These proportions make them larger than Chipping Sparrows, but smaller than Fox Sparrows.

Final Thoughts

According to the North American Breeding Bird Survey, Cassin’s Sparrow populations were stable or slightly declining between 1966 and 2015. However, since there is limited data on their whereabouts overall, their overall numbers relative to their historical numbers are difficult to gauge. Nevertheless, Partners in Flight has said that present data indicates that it is a species of low conservation concern. Nevertheless, they also estimate that if current population trends continue, the species will lose half its current population by 2086. Conservation threats to the species include the clearing of land for development, agriculture, or grazing.

Like most other Sparrows, they are especially susceptible to minute changes in their surrounding habitats. Furthermore, desert habitats that they depend on are further endangered as urban developmental schemes continue. When it comes to preserving the myriad of treasures that nature continues to offer to us, raising awareness about these treasures is the first and most foundational step. As we continue to find out more and more about the avian world that we always took for granted, our knowledge of them just continues to become more holistic. An incredible experience that can never fully be quantified.


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At the Bird Watching Academy & Camp we help kids, youth, and adults get excited and involved in bird watching. We have several monthly subscription boxes that you can subscribe to. Our monthly subscription boxes help kids, youth, and adults learn about birds, bird watching, and bird conservation.

Bird Watching Binoculars for IdentifyingCassin’s Sparrows

The most common types of bird watching binoculars for viewing Cassin’s Sparrows are 8×21 binoculars and 10×42 binoculars. Bird Watching Academy & Camp sells really nice 8×21 binoculars and 10×42 binoculars. You can view and purchase them here.

Cassin’s Sparrow Stickers

Stickers are a great way for you to display your love for bird watching and the Cassin’s Sparrow. We sell a monthly subscription sticker pack. The sticker packs have 12 bird stickers. These sticker packs will help your kids learn new birds every month.

Bird Feeders ForCassin’s Sparrows

There are many types of bird feeders. Bird feeders are a great addition to your backyard. Bird feeders will increase the chances of attracting birds drastically. Both kids and adults will have a great time watching birds eat at these bird feeders. There are a wide variety of bird feeders on the market and it is important to find the best fit for you and your backyard.

Bird HousesForCassin’s Sparrows

There are many types of bird houses. Building a bird house is always fun but can be frustrating. Getting a bird house for kids to watch birds grow is always fun. If you spend a little extra money on bird houses, it will be well worth every penny and they’ll look great.

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