Rufous-collared Sparrow
Encyclopedia
The Rufous-collared Sparrow, Zonotrichia capensis, is an American sparrow
found in a wide range of habitats, often near humans, from the extreme southeast of Mexico
to Tierra del Fuego
, and on the island of Hispaniola
. It is famous for its diverse vocalizations which have been intensely studied since the 1970s, particularly by Paul Handford and Stephen C. Lougheed (UWO
), Fernando Nottebohm
(Rockefeller University
) and Pablo Luis Tubaro (UBA
). Local names for this bird include the Portuguese tico-tico and the Spanish chingolo.
Young birds have a duller, indistinct head pattern, with brown stripes and a buff ground colour. They lack the rufous collar, and have streaked underparts.
There are between 25 and 29 subspecies
. In general, the smaller forms occur in coastal mountains, intermediate birds in the Andes
, and large, darker, forms breed on the tepui
s. The largest of the tepui subspecies, Z. c. perezchincillae, has grey underparts, and the rufous collar extends as a black band of freckles across the breast. This form might be separable as a distinct species, or it might just be a particularly distinct population due to genetic bottleneck effects.
. It can be seen in virtually any open or semi-open habitat, including cultivation, gardens, parks, grassland and scrubby second growth or cerrado
. It copes well with urban
and suburban environments, but is absent from the densely forested sections of the Amazon Basin
.
It is also scarce on the Guiana Shield, occurring mainly on some tepui
s and in the Pakaraima Mountains of Guyana
.
Explaining the presence of this species in the island of Hispaniola
and absence from the rest of the Caribbean basin
, may be a similar theory to the one proposed for the Hispaniolan Crossbill
(Loxia megaplaga). In that scenario, the bird's ancestors were present across the region during the much cooler climes of the last glacial period, but was left marooned in the highest Hispaniolan mountains once warming began.
The Rufous-collared Sparrow feeds on the ground on seeds, fallen grain, insect
s and spider
s. It will sometimes join mixed-species feeding flock
s and has been observed to pick termite
s from spider web
s. It is usually seen in pairs which hold small territories, or in small flocks. Tame and approachable, it is common throughout its large range and not considered threatened by the IUCN.
_e_(_zonotrichia_capensis_).jpg)
The breeding season is limited by food availability and ultimately rainfall. In the subtropical yungas
of NW Argentina, females begin to build nests around the end of October, when the wet season
comes, but by early December most nesting activity has already finished. By contrast, 2,000 meters ASL
in the Andes
of Pichincha Province
(Ecuador
), eggs were being incubated in December, and nest-building activity recorded in March and April, suggesting extended breeding throughout the wet season. The open cup nest consists of plant material lined with fine grasses. It is constructed in matted vegetation on the ground, low in a tree or bush, or in a niche in a wall, perhaps 2 meters high at best but usually less than half a meter above ground.
The female lays two or three pale greenish-blue eggs with reddish-brown blotches. The eggs measure approximately 19–21 mm by 15–16 mm and weigh 2.6–2.8 g each. They are incubated by the female for 12–14 days, during which she spends about two-thirds of the daytime brood or attend the nest in some other way. The male helps in feeding the chicks however, which stay in the nest for about two more weeks. They are not very voracious, and even as they approach fledging the parents will only feed them every 10 minutes or so. Brood parasitism, e.g. by the Shiny Cowbird
(Molothrus bonariensis), may occur, and breeding failure due to predation
is very frequent during the incubation period. Predation on nestlings, on the other hand, does not seem to occur more often than in similar-sized Passeroidea.
For subtropical/temperate populations in Argentina (except when noted), the song can be described as follows:
Songs are typically two-part: an introductory phrase (termed "theme" in the original description of the song) of 2 to 4 pure tone whistles, which are flat, rising, falling, or rising then falling in pitch, followed by a terminal trill, composed of several to many identical (or nearly so) elements. There is a high degree of stereotypy of song within individuals, both within and among seasons. The trill rate is locally very consistent, but varies greatly among populations, with inter-element interval ranging from 12 msec
. to 400 msec. or more.
Song measures:
Songs in the study populations were typically ~2–2.5 seconds in duration. The whistled theme notes are each ~0.25–0.5 s in duration, and are 2–3 in number in typical songs (from a sample of 1764 individuals, mean # notes/song = 2.87: 1-note themes – 0.5%; 2-note – 27.6%; 3-note – 58%; 4-note – 13%; 5-note – 0.8%; 7-note – 0.1%).
These notes are either 1) level, 2) rising, 3) falling, or 4) rising then falling in pitch. Absolute abundance of these note types: 1) – 15.9%; 2) – 32.0%; 3) – 39.8%; 4) – 11.4%. On a notes per song basis, note-type frequency is: 1) – 0.46; 2) – 0.92; 3) – 1.14; 4) – 0.32. Most of the energy in these notes lies between 4 and 6 kHz, with a range of 2.27–8.8 kHz. The terminal trill comprises several to many near-identical elements, which are descending frequency sweeps, with a maximum frequency of 3.8–8.7 kHz and a minimum frequency of 2.4–4.9 kHz.
_(2195772708).jpg)
Singing behaviour:
Individuals were found to sing for up to 30 minutes at a time, though usually 2–5 minutes. Countersinging is evident, though not well-studied. Singing-rate is regular, and usually 10–12 per minute. Typically from some elevated point, where available – a large rock, bush, etc. In open scrub and grassland, will sing from stem-tops. In suburban situations, will sing from low branches of trees, walls, sheds, etc. Individuals have "favourite" singing points, used repeatedly both within and among seasons. Flight songs have been recorded in migrating groups; these songs seem to be longer and more complex than typical territorial songs, and resemble night songs. Night-singing is recorded, though it is rare and unpredictable. Anecdotal evidence suggests that it may relate to stress. Night songs are typically unlike daytime songs, being longer and more complex.
Though there is a peak of singing activity near dawn, chingolos will sing strongly, if not persistently, at almost any time of day during the main season (September to January), except when mid-day temperatures are much above 30 °C (86 °F). There is a slight resurgence of activity in the evening.
In some areas (in arid
parts of NW Argentina
, in eastern Patagonia
, and in certain sites in Costa Rica
) there is often or always no terminal trill, and the song comprises whistles only. A few individuals in some few localities – so far only in montane
grasslands – show two terminal trills, the first rapid, the second substantially slower.
Females apparently do not sing, though this is not known with certainty. So far as is known (based on the Ph.D. thesis studies of Tubaro), development of vocal abilities seems to be very similar to the White-crowned Sparrow
(Z. leucophrys).
In the best-studied populations, in NW Argentina, songs appear highly stereotyped, with the great majority of individuals showing a single, song. There is good evidence that this song does not change among years, at least after first breeding. However, there is evidence from Ecuador
that tropical populations show individual repertoires of up to 7 diverse song types.
Seasonal variation is very little studied. There is unpublished evidence that in Patagonian populations in the early season individuals may sing more than one song. But this phenomenon seems to disappear by the time the breeding season is properly under way.
Argentina
. He interpreted his findings largely in the context established a few years before in the White-crowned Sparrow, that is, he suggested that these dialects perhaps serve to enhance the genetic integrity of local populations. The first direct investigation of this possibility, while providing no support for what came to be called the Genetic Adaptation Hypothesis (GAH), which explains the vocal dialects of the Brown-headed Cowbird
(Molothrus ater) well., showed that the spatial organisation of song variation was very closely associated with the distribution of distinct habitat types. Moreover, the structural characteristics of the dialect variable (trill interval) showed variation largely consistent with the interspecific acoustic patterns described by E.S. Morton, that is, in general, the trill interval varied from short (~50 ms; rapid trills) in open grasslands to long (1–200 ms; slow whistles) in woodlands and forests.
This ecological dimension was explored further by Handford and students in the highly diverse habitats of northwestern Argentina. They showed that the ecological ordering of dialect variation over a huge geographical space (1200 kilometre) and across a dramatic sweep of structurally distinct habitats (puna scrub, grassland, desert scrub, thorn woodland, and drought-deciduous forest (see Figure) was largely consistent with the previously established picture. This work also demonstrated that these spatial patterns show temporal stability of at least 20 years (now known to exceed 30 years), and stability on the order of centuries is implied by the persistence of certain habitat dialects long after the native vegetation has been removed by agriculture. This massive demonstration of acoustically rational habitat-based song variation strongly supports what is now known as the Acoustic Adaptation Hypothesis. However, the work also provided a basis for a final evaluation of the GAH on a similar geographical scale. This study showed that the substantial genetic variation shown by the species is organised largely by distance; dialect songs impose no further structure: it seems that for this species the GAH has no explanatory value.
The most recent work on this species confirms that the clear ecological segregation of acoustically rational vocal dialects in Argentina extends from 22ºS
at the Bolivia
n border south to 42ºS
in northern Patagonia
. Across this vast space, the greatest song diversity is concentrated in the vegetationally diverse north west; in the ecologically more uniform central and southern regions, great song uniformity is encountered; finally, island habitats, such as montane grasslands, are represented by repeated islands of the specific song dialect. Other recent work suggests, however, that tropical population (Ecuador
) do not show this pattern: instead, individuals show repertoires (from 1–7 trill-types; mean = ~4) and local populations can show nearly as much trill variation as is known from all Argentina.
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American sparrow
American sparrows are a group of mainly New World passerine birds, forming part of the family Emberizidae. American sparrows are seed-eating birds with conical bills, brown or gray in color, and many species have distinctive head patterns....
found in a wide range of habitats, often near humans, from the extreme southeast of Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
to Tierra del Fuego
Tierra del Fuego
Tierra del Fuego is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of a main island Isla Grande de Tierra del Fuego divided between Chile and Argentina with an area of , and a group of smaller islands including Cape...
, and on the island of Hispaniola
Hispaniola
Hispaniola is a major island in the Caribbean, containing the two sovereign states of the Dominican Republic and Haiti. The island is located between the islands of Cuba to the west and Puerto Rico to the east, within the hurricane belt...
. It is famous for its diverse vocalizations which have been intensely studied since the 1970s, particularly by Paul Handford and Stephen C. Lougheed (UWO
University of Western Ontario
The University of Western Ontario is a public research university located in London, Ontario, Canada. The university's main campus covers of land, with the Thames River cutting through the eastern portion of the main campus. Western administers its programs through 12 different faculties and...
), Fernando Nottebohm
Fernando Nottebohm
Dr Fernando Nottebohm is a neuroscientist and is the Dorothea L. Leonhardt Professor at Rockefeller University as well as being head of the Laboratory of Animal Behavior and director of the Field Research Center for Ecology and Ethology....
(Rockefeller University
Rockefeller University
The Rockefeller University is a private university offering postgraduate and postdoctoral education. It has a strong concentration in the biological sciences. It is also known for producing numerous Nobel laureates...
) and Pablo Luis Tubaro (UBA
University of Buenos Aires
The University of Buenos Aires is the largest university in Argentina and the largest university by enrollment in Latin America. Founded on August 12, 1821 in the city of Buenos Aires, it consists of 13 faculties, 6 hospitals, 10 museums and is linked to 4 high schools: Colegio Nacional de Buenos...
). Local names for this bird include the Portuguese tico-tico and the Spanish chingolo.
Description
The Rufous-collared Sparrow is 13.5–15 cm long and weighs 20–25 g. The adult has a stubby grey bill and a grey head with broad black stripes on the crown sides and thinner stripes through the eye and below the cheeks. The nape and breast sides are rufous and the upperpart are black-streaked buff-brown. There are two white wing bars. The throat is white, and the underparts are off-white, becoming brown on the flanks and with a black breast patch.Young birds have a duller, indistinct head pattern, with brown stripes and a buff ground colour. They lack the rufous collar, and have streaked underparts.
There are between 25 and 29 subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
. In general, the smaller forms occur in coastal mountains, intermediate birds in the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
, and large, darker, forms breed on the tepui
Tepui
A tepui , or tepuy, is a table-top mountain or mesa found in the Guiana Highlands of South America, especially in Venezuela. The word tepui means "house of the gods" in the native tongue of the Pemon, the indigenous people who inhabit the Gran Sabana....
s. The largest of the tepui subspecies, Z. c. perezchincillae, has grey underparts, and the rufous collar extends as a black band of freckles across the breast. This form might be separable as a distinct species, or it might just be a particularly distinct population due to genetic bottleneck effects.
Ecology
In the northern and western part of its range, this generally abundant bird is typically found at altitudes of 600 metre, but in the southern and eastern part it is commonly found down to near sea levelSea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
. It can be seen in virtually any open or semi-open habitat, including cultivation, gardens, parks, grassland and scrubby second growth or cerrado
Cerrado
The Cerrado, is a vast tropical savanna ecoregion of Brazil, particularly in the states of Gioas and Minas Gerais...
. It copes well with urban
Urban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
and suburban environments, but is absent from the densely forested sections of the Amazon Basin
Amazon Basin
The Amazon Basin is the part of South America drained by the Amazon River and its tributaries that drains an area of about , or roughly 40 percent of South America. The basin is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela...
.
It is also scarce on the Guiana Shield, occurring mainly on some tepui
Tepui
A tepui , or tepuy, is a table-top mountain or mesa found in the Guiana Highlands of South America, especially in Venezuela. The word tepui means "house of the gods" in the native tongue of the Pemon, the indigenous people who inhabit the Gran Sabana....
s and in the Pakaraima Mountains of Guyana
Guyana
Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...
.
Explaining the presence of this species in the island of Hispaniola
Hispaniola
Hispaniola is a major island in the Caribbean, containing the two sovereign states of the Dominican Republic and Haiti. The island is located between the islands of Cuba to the west and Puerto Rico to the east, within the hurricane belt...
and absence from the rest of the Caribbean basin
Caribbean Basin
The Caribbean Basin is generally defined as the area running from Florida westward along the Gulf coast, then south along the Mexican coast through Central America and then eastward across the northern coast of South America. This region includes the islands of the archipelago of the West Indies...
, may be a similar theory to the one proposed for the Hispaniolan Crossbill
Hispaniolan Crossbill
The Hispaniolan Crossbill is a crossbill that is endemic to the island of Hispaniola in the Caribbean and therefore only found in Haiti and the Dominican Republic....
(Loxia megaplaga). In that scenario, the bird's ancestors were present across the region during the much cooler climes of the last glacial period, but was left marooned in the highest Hispaniolan mountains once warming began.
The Rufous-collared Sparrow feeds on the ground on seeds, fallen grain, insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s. It will sometimes join mixed-species feeding flock
Mixed-species feeding flock
A mixed-species feeding flock, also termed a mixed-species foraging flock, mixed hunting party or informally bird wave, is a flock of usually insectivorous birds of different species, that join each other and move together while foraging...
s and has been observed to pick termite
Termite
Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...
s from spider web
Spider web
A spider web, spiderweb, spider's web or cobweb is a device built by a spider out of proteinaceous spider silk extruded from its spinnerets....
s. It is usually seen in pairs which hold small territories, or in small flocks. Tame and approachable, it is common throughout its large range and not considered threatened by the IUCN.
Yungas
The Yungas is a stretch of forest along the eastern slope of the Andes Mountains from southeastern Peru through central Bolivia. It is a transitional zone between the Andean highlands and the eastern forests. Like the surrounding areas, it has characteristics of the Neotropic ecozone...
of NW Argentina, females begin to build nests around the end of October, when the wet season
Wet season
The the wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region occurs. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the...
comes, but by early December most nesting activity has already finished. By contrast, 2,000 meters ASL
Above mean sea level
The term above mean sea level refers to the elevation or altitude of any object, relative to the average sea level datum. AMSL is used extensively in radio by engineers to determine the coverage area a station will be able to reach...
in the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
of Pichincha Province
Pichincha Province
Pichincha is a province of Ecuador located in the northern sierra region; its capital and largest city is Quito. It is bordered by Imbabura & Esmeraldas to the north, Cotopaxi & Santo Domingo de los Tsáchilas to the south, Napo & Sucumbíos to the east, and Esmeraldas & Santo Domingo de los...
(Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
), eggs were being incubated in December, and nest-building activity recorded in March and April, suggesting extended breeding throughout the wet season. The open cup nest consists of plant material lined with fine grasses. It is constructed in matted vegetation on the ground, low in a tree or bush, or in a niche in a wall, perhaps 2 meters high at best but usually less than half a meter above ground.
The female lays two or three pale greenish-blue eggs with reddish-brown blotches. The eggs measure approximately 19–21 mm by 15–16 mm and weigh 2.6–2.8 g each. They are incubated by the female for 12–14 days, during which she spends about two-thirds of the daytime brood or attend the nest in some other way. The male helps in feeding the chicks however, which stay in the nest for about two more weeks. They are not very voracious, and even as they approach fledging the parents will only feed them every 10 minutes or so. Brood parasitism, e.g. by the Shiny Cowbird
Shiny Cowbird
The Shiny Cowbird, Molothrus bonariensis, is a passerine bird in the New World family Icteridae. It breeds in most of South America apart from the most dense jungles, mountains and deserts , the coldest southernmost regions , and on Trinidad and Tobago...
(Molothrus bonariensis), may occur, and breeding failure due to predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
is very frequent during the incubation period. Predation on nestlings, on the other hand, does not seem to occur more often than in similar-sized Passeroidea.
Vocalizations
The Rufous-collared Sparrow has extensive geographical variation in its vocalisations, but calls include a sharp tsip. The male's song, given from a low perch, typically includes slurred whistles with or without a final trill, tee-teeooo, e’e’e’e’e, or teeooo, teeeee.For subtropical/temperate populations in Argentina (except when noted), the song can be described as follows:
Songs are typically two-part: an introductory phrase (termed "theme" in the original description of the song) of 2 to 4 pure tone whistles, which are flat, rising, falling, or rising then falling in pitch, followed by a terminal trill, composed of several to many identical (or nearly so) elements. There is a high degree of stereotypy of song within individuals, both within and among seasons. The trill rate is locally very consistent, but varies greatly among populations, with inter-element interval ranging from 12 msec
Millisecond
A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....
. to 400 msec. or more.
Song measures:
Songs in the study populations were typically ~2–2.5 seconds in duration. The whistled theme notes are each ~0.25–0.5 s in duration, and are 2–3 in number in typical songs (from a sample of 1764 individuals, mean # notes/song = 2.87: 1-note themes – 0.5%; 2-note – 27.6%; 3-note – 58%; 4-note – 13%; 5-note – 0.8%; 7-note – 0.1%).
These notes are either 1) level, 2) rising, 3) falling, or 4) rising then falling in pitch. Absolute abundance of these note types: 1) – 15.9%; 2) – 32.0%; 3) – 39.8%; 4) – 11.4%. On a notes per song basis, note-type frequency is: 1) – 0.46; 2) – 0.92; 3) – 1.14; 4) – 0.32. Most of the energy in these notes lies between 4 and 6 kHz, with a range of 2.27–8.8 kHz. The terminal trill comprises several to many near-identical elements, which are descending frequency sweeps, with a maximum frequency of 3.8–8.7 kHz and a minimum frequency of 2.4–4.9 kHz.
Individuals were found to sing for up to 30 minutes at a time, though usually 2–5 minutes. Countersinging is evident, though not well-studied. Singing-rate is regular, and usually 10–12 per minute. Typically from some elevated point, where available – a large rock, bush, etc. In open scrub and grassland, will sing from stem-tops. In suburban situations, will sing from low branches of trees, walls, sheds, etc. Individuals have "favourite" singing points, used repeatedly both within and among seasons. Flight songs have been recorded in migrating groups; these songs seem to be longer and more complex than typical territorial songs, and resemble night songs. Night-singing is recorded, though it is rare and unpredictable. Anecdotal evidence suggests that it may relate to stress. Night songs are typically unlike daytime songs, being longer and more complex.
Though there is a peak of singing activity near dawn, chingolos will sing strongly, if not persistently, at almost any time of day during the main season (September to January), except when mid-day temperatures are much above 30 °C (86 °F). There is a slight resurgence of activity in the evening.
Variation
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
parts of NW Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, in eastern Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
, and in certain sites in Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
) there is often or always no terminal trill, and the song comprises whistles only. A few individuals in some few localities – so far only in montane
Montane
In biogeography, montane is the highland area located below the subalpine zone. Montane regions generally have cooler temperatures and often have higher rainfall than the adjacent lowland regions, and are frequently home to distinct communities of plants and animals.The term "montane" means "of the...
grasslands – show two terminal trills, the first rapid, the second substantially slower.
Females apparently do not sing, though this is not known with certainty. So far as is known (based on the Ph.D. thesis studies of Tubaro), development of vocal abilities seems to be very similar to the White-crowned Sparrow
White-crowned Sparrow
The White-crowned Sparrow is a medium-sized sparrow native to North America.- Description :Adults are long and have black and white stripes on their head, a grey face, brown streaked upper parts and a long tail. The wings are brown with bars and the underparts are grey. Their bill is pink or yellow...
(Z. leucophrys).
In the best-studied populations, in NW Argentina, songs appear highly stereotyped, with the great majority of individuals showing a single, song. There is good evidence that this song does not change among years, at least after first breeding. However, there is evidence from Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
that tropical populations show individual repertoires of up to 7 diverse song types.
Seasonal variation is very little studied. There is unpublished evidence that in Patagonian populations in the early season individuals may sing more than one song. But this phenomenon seems to disappear by the time the breeding season is properly under way.
Vocal dialects
This ecologically catholic neotropical songbird provides perhaps one of the clearest and most widely distributed habitat-related dialect systems. The geographic variation in the song of this species became apparent over 30 years ago with F. Nottebohm's study in subtropical and temperateTemperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. He interpreted his findings largely in the context established a few years before in the White-crowned Sparrow, that is, he suggested that these dialects perhaps serve to enhance the genetic integrity of local populations. The first direct investigation of this possibility, while providing no support for what came to be called the Genetic Adaptation Hypothesis (GAH), which explains the vocal dialects of the Brown-headed Cowbird
Brown-headed Cowbird
The Brown-headed Cowbird is a small brood parasitic icterid of temperate to subtropical North America. They are permanent residents in the southern parts of their range; northern birds migrate to the southern United States and Mexico in winter, returning to their summer habitat around March or...
(Molothrus ater) well., showed that the spatial organisation of song variation was very closely associated with the distribution of distinct habitat types. Moreover, the structural characteristics of the dialect variable (trill interval) showed variation largely consistent with the interspecific acoustic patterns described by E.S. Morton, that is, in general, the trill interval varied from short (~50 ms; rapid trills) in open grasslands to long (1–200 ms; slow whistles) in woodlands and forests.
This ecological dimension was explored further by Handford and students in the highly diverse habitats of northwestern Argentina. They showed that the ecological ordering of dialect variation over a huge geographical space (1200 kilometre) and across a dramatic sweep of structurally distinct habitats (puna scrub, grassland, desert scrub, thorn woodland, and drought-deciduous forest (see Figure) was largely consistent with the previously established picture. This work also demonstrated that these spatial patterns show temporal stability of at least 20 years (now known to exceed 30 years), and stability on the order of centuries is implied by the persistence of certain habitat dialects long after the native vegetation has been removed by agriculture. This massive demonstration of acoustically rational habitat-based song variation strongly supports what is now known as the Acoustic Adaptation Hypothesis. However, the work also provided a basis for a final evaluation of the GAH on a similar geographical scale. This study showed that the substantial genetic variation shown by the species is organised largely by distance; dialect songs impose no further structure: it seems that for this species the GAH has no explanatory value.
The most recent work on this species confirms that the clear ecological segregation of acoustically rational vocal dialects in Argentina extends from 22ºS
22nd parallel south
The 22nd parallel south is a circle of latitude that is 22 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America....
at the Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
n border south to 42ºS
42nd parallel south
The 42nd parallel south is a circle of latitude that is 42 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, the Indian Ocean, Australasia, the Pacific Ocean and South America....
in northern Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
. Across this vast space, the greatest song diversity is concentrated in the vegetationally diverse north west; in the ecologically more uniform central and southern regions, great song uniformity is encountered; finally, island habitats, such as montane grasslands, are represented by repeated islands of the specific song dialect. Other recent work suggests, however, that tropical population (Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
) do not show this pattern: instead, individuals show repertoires (from 1–7 trill-types; mean = ~4) and local populations can show nearly as much trill variation as is known from all Argentina.
Further reading
- Byers, Olsson and Curson, Buntings and Sparrows ISBN 1-873403-19-4
- Hilty, Birds of Venezuela, ISBN 0-7136-6418-5
- Stiles and Skutch, A guide to the birds of Costa Rica, ISBN 0-8014-9600-4
- Handford, Paul. 2005 Latin accents: song dialects in a South American sparrow. Birding 37(5): 510-519.
- Handford, P. 1983. Continental patterns of morphological variation in a South American sparrow. Evolution 37: 920-930.
- Handford, P. 1985. Morphological relationships among subspecies of the Rufous-collared sparrow, Zonotrichia capensis. Can. J. Zool. 63: 2383-2388.
- Lougheed, S.C., A.J. Lougheed, M. Rae & P. Handford 1989 Analysis of a dialect boundary in chaco vegetation in the Rufous-collared sparrow. Condor 91: 1002-1005.
- Lougheed, S.C. & P. Handford 1989 Night songs in the Rufous-collared Sparrow. Condor 91: 462-465.
- Lougheed, S.C., P. Handford and A.J. Baker 1993 Mitochondrial DNA hyperdiversity, vocal dialects and subspecies in the Rufous-collared sparrow, (Zonotrichia capensis). Condor 95: 889-895.
- Miller, A.H. & V.D. Miller 1968 The behavioural ecology and breeding biology of the Andean Sparrow, Zonotrichia capensis. Caldasia 10: 83-154.
- Nottebohm, F. & R.K. Selander 1972 Vocal dialects and gene frequencies in the Chingolo sparrow, Zonotrichia capensis Condor 137-143.
- Nottebohm, F. 1975 Continental patterns of song variability in Zonotrichia capensis: some possible ecological correlates. Am. Nat. 109: 605-624.
- Tubaro, P., E. Segura and P. Handford. 1993 Geographic variation in the song of the Rufous-collared sparrow (Zonotrichia capensis) in eastern Argentina. Condor 95: 588-595
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