Sage sparrows (Amphispiza belli) are most commonly found in the Pacific region of the United States. The majority of their population lives in the south central region of San Diego County during the summer. Their breeding range includes the northern Campo Plateau, the south-facing Laguna Mountains, Otay, McGinty, Sycuan, Viejas, Guatay, Palomar [mountains], Rancita, and Dameron/Oak Grove valleys. The winter range of sage sparrows consists of the Torrey Pines State Reserve, east Carlsbad Agua Hedionda Creek, and north coastal San Diego County. Their migrational range extends throughout Fallbrook, Clark Dry Lake, and San Diego County (Unitt, 2012). (Unitt, 2012)
Sage sparrows are found in dense chaparral regions, typically where chamise is abundant. The lack of leaf litter in these areas allows them to run freely on the ground. Their habitats can also be comprised of open areas filled with creosote and saltbush. Such is the case in their winter habitats, which are typically valleys, sinks, or sandy washes, with diverse shrub varieties (Dunn et al., 2017). Sage sparrows occupy the shrubs located in chaparral and sagebrush habitats. These habitats are threatened by fires as well as human interference, such as agricultural conversion and urbanization (Martin and Carlson, 1998). Additionally, sage sparrows have been known to occupy arid shrub-steppe habitat composed of various shrubs and grasses. Sage sparrow habitats can be composed of big sagebrush, saltbush, green rabbitbush, gray rabbitbush, greasewood, bluegrass, wheatgrass, fescue, and brome. The presence of these plants - sagebrush particularly - in a chaparral habitat has been correlated with the presence of large populations of sage sparrows (Rotenberry and Knick, 1999). This is because such kinds of shrubs serve as important sage sparrow nesting sites (Turner, 2009). (Dunn, et al., 2017; Martin and Carlson, 1998; Rotenberry and Knick, 1999; Turner, 2009)
Sage sparrows are typically small, dark in color, and occupy chamise chaparral and coastal sage scrub. This differentiates them from other types of sparrows, which are more likely to be larger in size, have paler coloration, and occupy desert habitats (Cicero and Koo, 2012). Sage sparrows have dark-colored streaks on their flanks. Their dark coloration helps them remain hidden from predators in the shrubs where they reside (Chase et al., 2000). Their beaks are rounded as well as pointed to assist in eating. They have white stripes around their eyes and outer tail feathers, though their tails are primarily gray-black with almost no white showing. Their breasts are white, with a single, central dark spot. Their crowns are predominantly black. Adult sage sparrows are 12 to 15 cm in length and weigh 15 to 22 grams (Dunn et al., 2017). Adult males and females are quite similar looking. They do not display noticeable examples of sexual dimorphism and both sexes exhibit large, solid, black-colored throat stripes (Martin and Carlson, 1998). (Chase, et al., 2000; Cicero and Koo, 2012; Dunn, et al., 2017; Martin and Carlson, 1998)
Sage sparrows are distinct from many sparrows in that they are monogamous and each pair of birds pick their nest sites together. Female sage sparrows construct nests using coarse grass and twigs on the outside, and fine grass, thin bark, and feathers on the inside. Male sage sparrows sing on nearby perches and watch over their mates as they build nests.
Sage sparrows breed predominantly in sagebrush and chaparral environments in the Pacific region of the United States. Their nests are typically constructed in or under shrubs and dense, tall plants. In southern California, sage sparrows begin breeding during early spring. The exact dates depend on the latitude and elevation of their nesting sites. Sage sparrows depart for winter migration in mid-to-late September, after breeding takes place (Rotenberry and Wiens, 1989).
Sage sparrows select nest sites based on the level of vegetation present. It was found that sage sparrows nesting in areas with high levels of vegetation yielded greater reproductive success than those in areas with low levels of vegetation. The reproductive success of a nesting site was measured based on the number of fledglings from that site (Misenhalter and Rotenberry, 2000). The amount of rainfall and predation also have significant impacts on reproductive success. The sagebrush environments that experienced increased amounts of precipitation had greater reproductive success than those with decreased amounts of precipitation, since increased amounts of precipitation are correlated with high levels of vegetation growth. The effect of predation on nesting success depends on the type of predator as well as the intensity of predation that occurs in the given environment. Predation has been observed in greater quantities in nesting environments with low vegetation levels in comparison to high vegetation levels (Rotenberry and Wiens, 1989).
Sage sparrows have 1 to 3 broods during the early spring breeding season, with clutch sizes of 1 to 4 eggs. Their eggs are 1.8 to 2.0 cm in length and are bluish white or pale blue in color, with black or brown speckles. The incubation period of sage sparrows is 10 to 16 days and the nesting period is 9 to 10 days (Hansley and Beauvais, 2004). (Hansley and Beauvais, 2004; Misenhelter and Rotenberry, 2000; Rotenberry and Wiens, 1989)
The lifespan of sage sparrows is about 2 years for females and 3 years for males. Factors that impact their lifespans include disease, human interference, and predation. Adult birds are parasitized by chewing lice, philopterid lice, and trombiculid mites. A small portion of adult sage sparrows are also infected by avian pox. Additionally, nestlings are parasitized by botfly larvae and broods are parasitized by flesh flies (Martin and Carlson, 1998). The reduction of vegetation due to the introduction of grazing animals by humans has a significant impact on the lifespan of sage sparrows. The reproductive success of sage sparrows is also reliant on high levels of vegetation in nesting areas, and is therefore impacted by grazing animals as well. In addition, the presence of predators can affect the lifespan of sage sparrows. Predators like Townsend’s ground squirrels (Urocitellus townsendii), are the primary cause of mortality of nestlings. Therefore, such predators reduce the reproductive success of sage sparrows (Hansley and Beauvais, 2004). (Hansley and Beauvais, 2004; Martin and Carlson, 1998)
Sage sparrows forage for food by walking or hopping on the ground in areas with dense vegetation. They have also been known to run from shrub to shrub in open areas as a means of protection. Though they are more likely to run away than fly away when alarmed, sage sparrows are more likely to fly away in the breeding or winter seasons. Sage sparrow flights are smooth over long distances and choppy over short distances (Martin and Carlson, 1998).
Sage sparrows have been observed to chase other members of the same sex - males chase males and females chase females. While this is generally viewed as nonthreatening, male sage sparrows have also engaged in territorial behaviors that are more aggressive in nature. All males possess breeding territory, which usually does not overlap with others but has the potential to experience changes on a daily basis. Male sage sparrows defend their territories from others by taking part in visual displays of dominance or fighting (Rich, 1980). While mating, sage sparrows form pair bonds. Males will sing for females while females build nests, and pairs remain together for the course of a year. Male sage sparrow songs are used during the mating season and vary based on the geographic territory. When populations of sage sparrows occupy nearby geographic territories, it is likely that there will be major similarities in their songs, with minor differences that are only evident at the ends of songs (Rich, 1981). (Martin and Carlson, 1998; Rich, 1980; Rich, 1981)
Exact home ranges of sage sparrows are not reported. However, they are migratorial, covering a large range of Baja California and southern California in the U.S.
Sage sparrows communicate through a variety of song types. These song types include soft, high-pitched, bell-like songs that lasts a few seconds, multiple drawn out chirping sounds of varying frequencies, and low songs that maintain a singular pitch (Hansley and Beauvais, 2004). The most common sage sparrow song consists of an unfinished series of elongated notes that are rapid and muffled. Males use this type of song as a means of maintaining contact with females, since females do not have the ability to sing.
Males that have formed a mating pair sing less frequently than unpaired males. Males sing throughout the entire breeding season, but after young are fledged the frequency of their singing decreases. They typically sing simplistic songs at low frequencies from the tops of tall shrubs, where sounds carry farther (Hansley and Beauvais, 2004). Researchers found that the height of the shrubs impacts song quality by decreasing its clarity, scattering the sound, and causing wind interference (Kristan et al., 2003).
There is greater variation in sage sparrow songs between different populations in comparison to the variation within a single population. It was found that these different populations had greater song variation based on the song elements, song patterns, and the amount of birds that were present in the given population (Wiens, 1982). (Hansley and Beauvais, 2004; Kristan III, et al., 2003; Wiens, 1982)
The diet of sage sparrows varies depending on the season. Their diet during breeding season is described as that of a ground foraging omnivore who feeds on larval insects, adult insects, seeds, small fruits, plant material, spiders, and succulent vegetation. Their diet during non-breeding season (in early spring, fall, and winter months) can be described as that of a ground picking granivore, feeding on insects, plant material, and small seeds. Sage sparrows are able to forage and dig for the various types of food that make up their seasonal diets (Martin and Carlson, 1998).
Sage sparrows also acquire water from the consumption of insects and vegetation. As nestlings, fledglings, and adults, sage sparrows are primarily insectivorous. As nestlings and fledglings, sage sparrows favor eating arthropods such as grasshoppers or spiders, which are provided to them by their parents (Meents et al., 1982). (Martin and Carlson, 1998; Meents, et al., 1982)
Sage sparrows are targeted by a variety of predators during the different stages of their lives. Eggs and young are the targeted prey of Townsend’s ground squirrels (Urocitellus townsendii). Additionally, common ravens (Corvus corax) has been known to prey upon sage sparrow nests when nestlings are present. Other nest predators of sage sparrows include great horned owls (Bubo virginianus), loggerhead shrikes (Lanius ludovicianus), merlins (Falco columbarius), and greater roadrunners (Geococcyx californianus) (Martin and Carlson, 1998). A portion of nest-tending adults and unsuccessful nests have also been lost as a result of disease or parasitism. Brown-headed cowbirds (Molothrus ater) are a well-known parasite of sage sparrow nests during their breeding season. Additionally, diseases caused by botflies, chewing lice, flesh flies, fly larvae, and mites have the potential to affect the bodies of sage sparrows (Hansley and Beauvais, 2004). (Hansley and Beauvais, 2004; Martin and Carlson, 1998)
Sage sparrows live in ecosystems that often experience interference in the form of habitat degradation and human interference, such as the introduction of grazing animals. Their habitats are primarily composed of shrubs and shrub-like plants that are in danger of being destroyed by chemical or mechanical means. This habitat degradation takes place in order to provide the proper landscape to ensure the growth of grasses that provide nutrients for grazing animals. This habitat degradation can severely decrease the distribution of sage sparrows (Martin and Carlson, 1998). Human expansion also significantly impacts the ecosystems of sage sparrows. This is based on the knowledge that the proximity of humans to sage sparrow increases their chances of being preyed upon by feral cats. Sage sparrows have experienced serious levels of fragmentation due to the introduction of secondary predation on top of the existing predation efforts and brood parasitism.
The introduction of grazing animals also negatively affects sage sparrow habitat and can cause serious population decreases in chaparral or sagebrush environments. Domestic goats (Capra aegagrus hircus) and pigs (Sus scrofa domesticus) are two important examples of grazing animals that take part in such ecosystem destruction. However, threatened habitats and ecosystem as a whole can be recovered if grazing animals are removed (Martin and Carlson, 1998). (Martin and Carlson, 1998)
Sage sparrows are of economic importance to people because of their ability to inhabit various types of chaparral and sagebrush environments. They have the ability to blend into surrounding environments that are in close proximity to humans and in remote regions due to their muted coloration. Humans also study these birds in order to understand specific problems presented in the field of biology, such as avian evolution and methods that can be used to prevent population decreases in bird species. Sage sparrows are non-invasive and are not known to aggressively compete against other bird species for food. However, they do exhibit some aggressive behavior when involved in intraspecific competition. Sage sparrows do not play a role in the consumption of agricultural seeds that are produced by farm fields. They also do not communicate loudly or frequently, as communication is typically limited to breeding season. When they do communicate, it is not known to inconvenience humans (Hansley and Beauvais, 2004). (Hansley and Beauvais, 2004)
Sage sparrows are not known to be associated with negative economic impacts.
Sage sparrows are considered to be a species of special concern in the state of California. This classification is given to species declining in population size. The Western Working Group of Partners in Flight are active in their development of strategies regarding conservation management of the sage sparrow populations. Some of these strategies include protecting chaparral or sagebrush habitats from overgrazing, limiting the degradation of such areas, and prioritizing ahbitats that will ensure the growth of the sage sparrow populations (Martin and Carlson, 1998). Sage sparrows are becoming a species of major concern, based on the declining abundance and population distribution observed by the North American Breeding Bird Survey (BBS). The primary causes of their declining populations include the limited amount and quality of intact breeding habitat. However, not all government organizations agree that sage sparrows are a species of concern in California. The USDI Fish and Wildlife Service maintains that sage sparrows are not a species of conservation concern in California, but the USDI Bureau of Land Management states that they are a sensitive species. The USDA Forest Service also identifies sage sparrows as a sensitive species. In addition, the IUCN Red List recognizes sage sparrows as a priority avian species that needs to be conserved. They also note that there is concern that the species population is declining at a rapid rate (Hansley and Beauvais, 2004). (Hansley and Beauvais, 2004; Martin and Carlson, 1998)
Nikolija Jojic (author), California State University, San Marcos, Tracey Brown (editor), California State University, San Marcos, Galen Burrell (editor).
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
uses sound to communicate
living in landscapes dominated by human agriculture.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
union of egg and spermatozoan
an animal that mainly eats leaves.
an animal that mainly eats fruit
an animal that mainly eats seeds
An animal that eats mainly plants or parts of plants.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
parental care is carried out by males
Having one mate at a time.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
an animal that mainly eats all kinds of things, including plants and animals
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
scrub forests develop in areas that experience dry seasons.
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
places a food item in a special place to be eaten later. Also called "hoarding"
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
uses sight to communicate
Chase, M., W. Kristan III, A. Lyman, M. Price, J. Rotenberry. 2000. Single species as indicators of species richness and composition in California coastal sage scrub birds and small mammals. Conservation Biology, 14(2): 474-487.
Cicero, C., M. Koo. 2012. The role of niche divergence and phenotypic adaptation in promoting lineage diversification in the Sage Sparrow (Artemisiospiza belli, Aves: Emberizidae). Biological Journal of the Linnean Society, 107(2): 332-354.
Dunn, J., J. Alderfer, P. Lehman. 2017. National Geographic field guide to the birds of North America. Washington, D.C.: National Geographic.
Hansley, P., G. Beauvais. 2004. Species assessment for sage sparrow (Amphispiza belli) in Wyoming. Cheyenne, Wyoming, USA: United States Department of the Interior, Bureau of Land Management, Wyoming State Office.
Kristan III, W., A. Lynam, M. Price, J. Rotenberry. 2003. Alternative causes of edge‐abundance relationships in birds and small mammals of California coastal sage scrub. Ecology, 26(1): 29-44.
Martin, J., B. Carlson. 1998. "Bell’s Sparrow (Artemisiospiza belli), version 2.0. In The Birds of North America (A.F. Poole, Editor)" (On-line). Accessed April 20, 2020 at https://birdsna.org/Species-Account/bna/species/belspa2.
Meents, J., B. Anderson, R. Ohmart. 1982. Vegetation relationships and food of Sage Sparrows wintering in honey mesquite habitat. The Wilson Bulletin, n/a: 129-138.
Misenhelter, M., J. Rotenberry. 2000.
Choices and consequences of habitat occupancy and nest site selection in Sage Sparrows. Ecology, 81(10): 2892-2901.
Rich, T. 1981. Microgeographic variation in the song of the sage sparrow. The Condor, 83(2): 113-119.
Rich, T. 1980. Territorial behavior of the Sage Sparrow: spatial and random aspects. The Wilson Bulletin, n/a: 425-438.
Rotenberry, J., S. Knick. 1999. Multiscale habitat associations of the Sage Sparrow: implications for conservation biology. Studies in Avian Biology, 19: 95-103.
Rotenberry, J., J. Wiens. 1989. Reproductive biology of shrubsteppe passerine birds: geographical and temporal variation in clutch size, brood size, and fledging success. The Condor, 91(1): 1-14.
Turner, J. 2009. Habitat associations of the San Clemente sage sparrow (Amphispiza belli clementeae).. n/a, n/a: n/a.
Unitt, P. 2012. "Sage Sparrow “Amphispiza belli" (On-line). Accessed March 10, 2020 at http://sdplantatlas.org/BirdAtlas/BirdPages.aspx.
Wiens, J. 1982. Song pattern variation in the sage sparrow (Amphispiza belli): Dialects or epiphenomena?. The Auk, 99(2): 208-229.