Dickcissel
Encyclopedia
The Dickcissel is a small American
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

 seed-eating bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

 in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Cardinalidae. It is the only member of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Spiza, though some sources list another supposedly extinct species (see below). In older works, it is often placed with the American sparrow
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....

s in the Emberizidae
Emberizidae
The Emberizidae are a large family of passerine birds. They are seed-eating birds with a distinctively shaped bill.In Europe, most species are called buntings. In North America, most of the species in this family are known as sparrows, but these birds are not closely related to the sparrows, the...

; females especially resemble American sparrow
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....

s in plumage.

Description

Dickcissels have a large pale bill, a yellow line over the eye, brownish upperparts with black streaks on the back, dark wings, a rust patch on the shoulder and light underparts. Adult males have a black throat patch, a yellow breast and grey cheeks and crown. This head and breast pattern is especially brilliant in the breeding plumage, making it resemble an Eastern Meadowlark
Eastern Meadowlark
The Eastern Meadowlark, Sturnella magna, is a medium-sized icterid bird, very similar in appearance to the Western Meadowlark. It occurs from eastern North America to South America, where it is also most widespread in the east.-Description:...

. Females and juveniles are brownish on the cheeks and crown and are somewhat similar in appearance to House Sparrow
House Sparrow
The House Sparrow is a bird of the sparrow family Passeridae, found in most parts of the world. One of about 25 species in the genus Passer, the House Sparrow occurs naturally in most of Europe, the Mediterranean region, and much of Asia...

s; they have streaked flanks.

In flight they make a low, "electric", buzzing fpppt. From an open perch in a field, this bird's song is a sharp dick dick followed by a buzzed cissel, also transcribed as skee-dlees chis chis chis or dick dick ciss ciss ciss.

Systematics and taxonomy

The Dickcissel is part of a group of Cardinalidae that apparently also includes Amaurospiza
Amaurospiza
Amaurospiza is a genus of birds. These "seedeaters" were formerly associated with the American sparrows and placed in the Emberizidae or the Fringillidae. The generic name is derived from the Ancient Greek amauros + spiza .Actually, they are part of the tanager-cardinal lineage...

, Cyanocompsa
Cyanocompsa
Cyanocompsa is a genus of cardinal in the Cardinalidae family.It contains the following species:* Ultramarine Grosbeak * Blue Bunting * Blue-black Grosbeak...

, Cyanoloxia
and Passerina
Passerina
The genus Passerina is a group of birds in the Cardinal family Cardinalidae. Although not directly related to buntings in the family Emberizidae, they are sometimes known as the North American buntings .The males show vivid colours in the breeding season; the...

. Spiza is the only one among these that lacks blue structural colors in its plumage. The scientific name means simply "American finch"; spiza is the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 catch-all term for finch
Finch
The true finches are passerine birds in the family Fringillidae. They are predominantly seed-eating songbirds. Most are native to the Northern Hemisphere, but one subfamily is endemic to the Neotropics, one to the Hawaiian Islands, and one subfamily – monotypic at genus level – is found...

-like birds. Many bird genera contain the term spiza, but none of these were generally held to be a really close relative of Spiza itself. Amusingly, Amaurospiza seems to have turned out to be one of the closest living relatives of the Dickcissel after all.

Though the color pattern and habits of the Dickcissel make it stand apart from other Cardinalidae, its robust cone-shaped bill - stouter than in American sparrow
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....

s or true finches which it somewhat resembles at first glance - gives away its relationships.

"Townsend's Dickcissel"

A problematic specimen is often discussed under the name of Spiza townsendi (or Spiza townsendii, the original misspelt specific name proposed by John James Audubon
John James Audubon
John James Audubon was a French-American ornithologist, naturalist, and painter. He was notable for his expansive studies to document all types of American birds and for his detailed illustrations that depicted the birds in their natural habitats...

). This individual was collected on May 11, 1833, by Audubon's colleague John Kirk Townsend
John Kirk Townsend
John Kirk Townsend was an American naturalist, ornithologist and collector.Townsend was born in Philadelphia and trained as a physician and pharmacist. He developed an interest in natural history in general and bird collecting in particular...

 in New Garden Township
New Garden Township, Pennsylvania
New Garden Township is a township in Chester County, Pennsylvania, United States. The population was 11,984 at the 2010 census. New Garden is the center of the mushroom agribusiness in southeastern Pennsylvania with a higher concentration of composting, mushroom growing, packaging, and shipping...

, Chester County, Pennsylvania
Chester County, Pennsylvania
-State parks:*French Creek State Park*Marsh Creek State Park*White Clay Creek Preserve-Demographics:As of the 2010 census, the county was 85.5% White, 6.1% Black or African American, 0.2% Native American or Alaskan Native, 3.9% Asian, 0.0% Native Hawaiian, 1.8% were two or more races, and 2.4% were...

. The specimen remains unique and nothing is known about what it represents with certainty; it has thus even been suggested to be an extinct relative.

It is commonly called "Townsend's Dickcissel" (or "Townsend's Bunting", "Townsend's Finch") in reference to the collector whom the scientific name honors. Rather than a distinct species or subspecies, it is (as certainly as this can be said in absence of direct proof) a color variant. Comparing the birds, it is immediately obvious that the yellow lipochrome
Lipochrome
Lipochrome is a form of pigment associated with amber and gold tones in human eyes and the eyes of other mammals.The term carotenoid is sometimes considered a synonym, but that term usually refers to specific molecules, while lipochrome refers to accumulations of varied molecules....

 pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

s are entirely absent in "Townsend's Dickcissel". The specimen has foxed
Foxing
Foxing is a term describing the age-related spots and browning seen on vintage paper documents such as books, postage stamps, certificates, and so forth. The name may derive from the fox-like reddish-brown color of the stains, or the rust chemical ferric oxide which may be involved...

 today, giving it an altogether beige hue, but when originally shot, the olive areas of the head were grey as the cheeks, and the yellow and buff on face and underside was pure white. The brown wings and tail were rufous, due to the pheomelanins not being tinged by lipochromes.

A color mutation?

Thus, this bird is very likely certainly the result of a simple genetic change, perhaps just a single point mutation
Point mutation
A point mutation, or single base substitution, is a type of mutation that causes the replacement of a single base nucleotide with another nucleotide of the genetic material, DNA or RNA. Often the term point mutation also includes insertions or deletions of a single base pair...

, affecting some part of the carotinoid metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

 - essentially the same thing that happens in albinism
Albinism
Albinism is a congenital disorder characterized by the complete or partial absence of pigment in the skin, hair and eyes due to absence or defect of an enzyme involved in the production of melanin...

 but in a different metabolic pathway
Metabolic pathway
In biochemistry, metabolic pathways are series of chemical reactions occurring within a cell. In each pathway, a principal chemical is modified by a series of chemical reactions. Enzymes catalyze these reactions, and often require dietary minerals, vitamins, and other cofactors in order to function...

. Though the bird seemed to be healthy and had survived to maturity when it found its untimely end through Townsend's gun, no other such specimens have been documented before, nor ever since. Albinism and other pigment aberrations are not infrequently seen in birds, and the lack of further specimens is somewhat puzzling in that respect.

No specific details are known about the Dickcissel's lipochrome metabolism; it may be that it happens to be more fine-tuned than in other birds, so that most mutations therein will be lethal and Audubon's bird was simply one of the very few individuals that survived. It stands to note that in wild birds, varying from species to species some color aberrations are less frequently seen than others, and that in captive birds such as canaries
Domestic Canary
The Domestic Canary, often simply known as the canary, is a domesticated form of the wild Canary, a small songbird in the finch family originating from the Macaronesian Islands ....

, some color mutations have only arisen a handful of times at most during several centuries of dedicated breeding and screening for novel color variants (see also Budgerigar colour genetics). While only a complete molecular biological
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

 study of the Dickcissel's metabolism and the specimen's ancient DNA
Ancient DNA
Ancient DNA is DNA isolated from ancient specimens. It can be also loosely described as any DNA recovered from biological samples that have not been preserved specifically for later DNA analyses...

 stands any reasonable chance to resolve the question with certainty, the hypothesis of an extremely uncommon color mutation is plausible, and such phenomena certainly occur in other Passeroidea.

A hybrid?

Alternatively, the bird was considered a hybrid, but the present state of knowledge of the Dickcissel's relations makes this not very plausible - there are a number of species with which Spiza could conceivably produce hybrids - such as Passerella -, but the lack of even the slightest hint of blue structural colors in Townsend's specimen and it moreover being not different from a Dickcissel in habitus
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

 makes the hybrid theory suspect. Regardless, Townsend noted observed the bird making vocalizations reminiscent more of an Indigo Bunting
Indigo Bunting
The Indigo Bunting, Passerina cyanea, is a small seed-eating bird in the family Cardinalidae. It is migratory, ranging from southern Canada to northern Florida during the breeding season, and from southern Florida to northern South America during the winter. It often migrates by night, using the...

 (Passerina cyanea), and by comparing mitochondrial and nuclear DNA
Nuclear DNA
Nuclear DNA, nuclear deoxyribonucleic acid , is DNA contained within a nucleus of eukaryotic organisms. In mammals and vertebrates, nuclear DNA encodes more of the genome than the mitochondrial DNA and is composed of information inherited from two parents, one male, and one female, rather than...

 sequences of the specimen with those of the Dickcissel, the Indigo Bunting, and perhaps other Passerina, the hybridization hypothesis should be far more easy to prove or reject than a color aberration. On the other hand, there is not enough known on whether Dickcissels pick up their characteristic vocalizations from conspecific males or whether they are innate, and thus no firm conclusion regarding Townsend's observations is presently possible.

An extinct species?

The notion that "Townsend's Dickcissel" represents an extinct species appears entirely without merit. Hybridization e.g. in Passerina
Passerina
The genus Passerina is a group of birds in the Cardinal family Cardinalidae. Although not directly related to buntings in the family Emberizidae, they are sometimes known as the North American buntings .The males show vivid colours in the breeding season; the...

is well documented to occur often, and the hybrids are often fertile to some extent. As the capability to produce intergeneric hybrids is almost always the same among closely related bird genera, there is nothing to indicate that the Dickcissel and a hypothetical congener would not have been able to produce fertile hybrid males at least (see Haldane's Rule
Haldane's rule
Haldane's rule or Haldane's law was formulated in 1922 by the British evolutionary biologist J.B.S. Haldane. It describes hybrid sterility in species and is extended to describe speciation in evolutionary theory, in two parts: the rule of hybrid sterility and the rule of hybrid inviability...

). Considering that, and the time and place where Townsend got his specimen - at a popular stopover region for Dickcissels returning from their South American winter quarters, and right at the time when the species is present in this region - it is hardly conceivable how "Townsend's Dickcissel" should have been, as has been suggested, "the very last remnant of a now extinct species".

That a closely related congener of Spiza americana, with which it almost certainly would have hybridized to some extent as well as shared at least a migration
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

 route and habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

, possibly even the breeding range
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...

, would even have evolved in the first place almost beggars belief. Though there are numerous sister species of songbirds occurring west and east of the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...

 for example, these do not differ in such a striking but easily explained way. Rather, their differences are usually more subtle but deep-rooted, for example vocalizations or details of the color pattern. Of course, it must be said to Audubon's credit that at his time neither theories of evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

 nor of biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...

 or phylogeny were accepted, and so his error is excusable. This cannot be held in favor of those 20th century writers who still claimed "Townsend's Dickcissel" to be a recently-extinct species.

Ecology

Their breeding habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...

 is fields in midwestern North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. They migrate
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

 in large flocks to southern 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...

, Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

, and northern South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. They may occur as vagrants well outside of their normal range.

Dickcissels forage on the ground or in fields. They mainly eat 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 seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s. Outside of the nesting season, they usually feed in flocks. They are considered a pest by farmers in some regions because flocks can consume large quantities of cultivated grain
Cereal
Cereals are grasses cultivated for the edible components of their grain , composed of the endosperm, germ, and bran...

s.

The birds migrate to their breeding range rather late, with the first arriving only in May, with most birds only arriving in early June. They nest near the ground in dense grasses or small shrubs, or up to 3–4 ft (90–120 cm) high in bushes and trees. Males may have up to six mates, with most attracting only one or two, and several failing to attract any mates at all. Yet if such "bachelors" survive until next summer, they will get another try to attract females, as the partners only stay together for raising one brood. Dickcissels are thus among the few songbird
Songbird
A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...

s that are truly polygynous. When they leave for winter quarters by early August or so, what little pair bond existed during the summer is broken up.

Dickcissel populations frequently fluctuate in numbers, even to the extent that their range changes notably. In the early 19th century, Dickcissels expanded eastward, establishing a population in New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...

 and the mid-Atlantic states
Mid-Atlantic States
The Mid-Atlantic states, also called middle Atlantic states or simply the mid Atlantic, form a region of the United States generally located between New England and the South...

 that disappeared around the end of the century. Both appearance and disappearance were probably related to changes in land use.

In Popular Culture

A Dickcissel known as Yelling Bird appears in the popular webcomic
Webcomic
Webcomics, online comics, or Internet comics are comics published on a website. While many are published exclusively on the web, others are also published in magazines, newspapers or often in self-published books....

 by Jeph Jacques
Jeph Jacques
Jeph Jacques writes and illustrates the webcomic Questionable Content. He was born in Rockville, Maryland, and graduated from Hampshire College with a degree in music...

, Questionable Content
Questionable Content
Questionable Content is a slice-of-life webcomic written and drawn by Jeph Jacques. It was launched on August 1, 2003. Jacques currently makes his living exclusively from QC merchandising and advertising, making him one of the few professional webcomic artists...

. He was originally a character in the side project IndieTits, but has in more recent times been used in filler strips over holidays and in unforeseen circumstances which prevent the author from creating a usual full strip.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK