The Great-tailed Grackle (Quiscalus mexicanus) is a large, noisy blackbird that is often seen in large groups, both when foraging and when gathering to roost overnight. These grackles are are found in a wide range of semi-open and open habitats . They are resident from the southwestern and south-central United States and northern Baja California (present during the breeding season somewhat farther north) south to northern South America. This species has expanded its range northward in recent decades. Great-tailed Grackles forage mainly on the ground, feeding on a range of small arthropods, vertebrates, and other animals, as well as seeds, waste grain, and fruits. Great-tailed Grackles nest in colonies that may include anywhere from a few pairs to hundreds of pairs. Historically, this species and the Boat-tailed Grackle (Quiscalus major) were considered to be conspecific (i.e., members of the same species), but they were later found to co-exist without interbreeding from southwestern Louisiana to southeastern Texas (U.S.A.). (Kaufman 1996; AOU 1998)
- American Ornithologists' Union. 1998. Check-list of North American Birds, 7th edition. American Ornithologists' Union, Washington, D.C.
- Kaufman, K. 1996. Lives of North American Birds. Houghton Mifflin, Boston.
The great-tailed grackle, Quiscalus mexicanus, was historically almost exclusively found in South and Central America, but human alteration of the environment has caused the birds to expand their range to include parts of the United States and Canada (Christensen, 2000). Their current range in the United States is north to eastern Oregon, with individuals sighted as far north as Canada (Sauer et al., 1997), south to northwest Peru, and as far east as Western Arkansas (Jaramillo, 1999).
Biogeographic Regions: nearctic (Native ); neotropical (Native )
Global Range: Resident from southeastern California and southern Nevada east to southern Nebraska and southwestern Missouri, south to South America (coastally to northwestern Peru and northwestern Venezuela). Breeding range is expanding. Recently nesting has occurred in Oregon and probably in Idaho (see Scheuering and Ivey 1995, Wilson Bull. 107:562-563).
Regularity: Regularly occurring
Type of Residency: Year-round
occurs (regularly, as a native taxon) in multiple nations
The male great-tailed grackle is a large blackbird that appears purple-glossed. He averages approximately 45 cm in length and has a long ample tail. A potential identification problem exists between the boat-tailed grackle and the great-tailed, but the tail of the great-tailed tends to be wider and longer. The female is brown with a pale breast, and averages 35 cm in length. Both sexes have distinctive yellow eyes as adults (Peterson, 1990).
Other Physical Features: endothermic ; bilateral symmetry
Length: 46 cm
Weight: 191 grams
Habitat and Ecology
The great-tailed grackle is found in a variety of habitats, including groves, thickets, farms, towns, city parks, (Peterson, 1990), mangroves, and marshes (Jaramillo, 1999).
Habitat Regions: temperate ; tropical
Aquatic Biomes: coastal
Other Habitat Features: urban ; suburban ; agricultural ; riparian
Comments: Partly open situations with scattered trees, cultivated lands, pastures, shores of watercourses, swamps, wet thickets, around human habitation, sometimes in marshes. Often roosts in village shade trees or urban parks (Stiles and Skutch 1989). South America: common locally in mangroves and along shorelines and on lawns and in parks in towns and cities (Ridgely and Tudor 1989). Nests in trees, bushes, man-made structures, mostly near or over water; marsh vegetation where no trees or bushes are available near water. Sometimes nests in heron colony.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Migratory at northern edge of breeding range.
The great-tailed grackle is known to eat insects, lizards, aquatic invertebrates and vertebrates, fruit, grain, and grass seed (Sibley, 2001). They are also known to remove and eat ectoparasites from livestock. Male nestlings appear to require more food than females of the same age (Ehrlich et al., 1988).
Animal Foods: reptiles; fish; eggs; insects; terrestrial non-insect arthropods
Plant Foods: seeds, grains, and nuts; fruit
Primary Diet: omnivore
Comments: Eats mostly various invertebrates, sometimes small fishes, amphibians, and bird eggs and nestlings, also grain; forages on ground, mud flats, and in shallow water (Terres 1980). Eats berries and larger fruits, newly planted and ripening grain, larvae extracted from ground, ticks removed from cattle, various invertebrates and small vertebrates, carrion, offal, etc. (Stiles and Skutch 1989).
Known prey organisms
This list may not be complete but is based on published studies.
Life History and Behavior
The female of the species incubates the egg for 13-14 days. The chicks are born immobile, downless, with their eyes closed, and need to be fed by a parent. (Altricial development). The young leave the nest after a period of 20 to 23 days, and the female tends to them. (Sibley 2001).
A banded great-tailed grackle lived at least 12.5 years. (USGS, 2002)
Status: wild: 12.5 (high) years.
Status: wild: 150 months.
Lifespan, longevity, and ageing
Early in the spring males establish small territories and begin the process of attracting females. The breeding is polygynous, and the females nest in the territory of one male. Several females will nest in a single male's territory, and mate with him. First year males are excluded from breeding but young females are not. The main display is the "ruff-out" which is accompanied by a song. In the "ruff-out" the tail is fanned while the body feathers are ruffed and the head is arched upwards as it sings. The wings are drooped and quivered or held out towards the sides. The male courtship display differs in that it is more exaggerated, the bill is pointed down rather than up, and the wings are rapidly quivered while the bird produces distinctive "cheat" notes. The female may respond by drooping and quivering the wings as the tail is cocked and gives "che" calls. (Jaramilo 1999)
Mating System: polygynous
First year males are excluded from mating, but young females (1 yr.) are not (Jaramillo, 1999). The breeding season begins in early April. Nesting occurs in colonies of few to thousands, with the nests placed close together. The males tend to avoid confrontation with low key disputes. The females will fight over the choice of nest sites, and will steal nest building materials from one another. Clutch sizes tend to average 3 to 4 eggs, and females incubate them for 13 to 15 days. The young are born altricial and leave the nest at 20 to 23 days (Harrison, 1978).
Breeding season: Spring
Range eggs per season: 3 to 4.
Range time to hatching: 13 to 15 days.
Range fledging age: 20 to 23 days.
Range age at sexual or reproductive maturity (female): 1 to 2 years.
Range age at sexual or reproductive maturity (male): 1 to 2 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual
Average eggs per season: 3.
Chicks are born immobile, downless, with their eyes closed, and need to be fed by a parent. The males do not participate in nesting or care of the young.
Parental Investment: altricial ; female parental care
Clutch size is 3-4 in north, 2-3 in Costa Rica. Sometimes produces two broods per year. Incubation, by female, lasts 13-14 days. Young are tended by female, leave nest at 20-23 days. Usually nests in aggregations. Males polygynous.
Molecular Biology and Genetics
Barcode data: Quiscalus mexicanus
There are 12 barcode sequences available from BOLD and GenBank. Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species. See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Quiscalus mexicanus
Public Records: 11
Specimens with Barcodes: 22
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
- 2008Least Concern
- 2004Least Concern
Over the past 30 years the great-tailed grackle has expanded its range in the U.S. at a rate of greater than 2.5% annually. This expansion is due to human modification of the landscape. Irrigation in arid areas, urbanization, and increasing cropland have all contributed to this expansion of range.(Christensen 2000)
US Migratory Bird Act: no special status
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Global Short Term Trend: Increase of 10 to >25%
Comments: Breeding Bird Survey data indicate a significant population increase in North America between 1966 and 1989 (Droege and Sauer 1990).
Management Requirements: See Tipton (1989) and Tipton et al. (1989) for methods for controlling grackle damage to citris.
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
Adult males are nearly granivorous (Jaramillo, 1999)
Negative Impacts: crop pest
Economic Importance for Humans: Positive
May aid in agricultural pest control.
Comments: Widely regarded as pest in Costa Rica, where it spread inland with agriculture and clearing in 1900s (Stiles and Skutch 1989). Damages citrus crops in Lower Rio Grande Valley (Johnson et al. 1989).
The Great-tailed Grackle or Mexican Grackle (Quiscalus mexicanus) is a medium-sized, gregarious passerine bird native to North and South America. A member of the family Icteridae, it is one of ten extant species of grackle and is closely related to the Boat-tailed Grackle and the Slender-billed Grackle. It is sometimes referred to as a “blackbird”. It is a New World blackbird and unrelated to any of the five species of Old World blackbirds (all of which are species of the Turdus genus). Similarly, it is often called “cuervo” in areas of Mexico owing to its glossy black plumage, although it is not a member of the genus Corvus, nor even of the family Corvidae.
Males reach up to 43 cm (17 in), including a tail that is almost as long as the body, weigh 230 g, and are jet-black with a violet-blue iridescent sheen to the feathers. Females are significantly smaller at 33 cm (13 in), weigh 125 g, and are mainly brownish-black, with a pale brown throat and belly. This morphological difference between males and females of a species is known as sexual dimorphism.
The Great-tailed Grackle and Boat-tailed Grackle were once considered the same species. Some species of grackle, usually the Great-tailed, are confused with an American Crow when people unfamiliar with bird identification are asked to identify a dead blackbird. This usually occurs when birds need to be identified as candidates for West Nile virus.
Distribution and habitat 
Its range stretches from Kansas in the northeast to southern California in the northwest down to northwest Peru and northwest Venezuela in the south; the grackle's range has been expanding north and west in recent years. It is common in Texas and Arizona in the southern regions. It is commonly found in agricultural regions and suburban environments, feeding on fruits, seeds, and invertebrates.
This bird has a large variety of raucous, cacophonous calls, some very melodic, but is considered to be a noisy pest species by some.  Its range expansion has not been aided by human introduction.
The females can travel in flocks and they share food. When a male spots a female, he engages her by puffing up and gaping his mouth. He then proceeds to make loud calls and follow the female. The female will allow the large males to mate with her; she will usually reject smaller males. Before dawn and after sundown these birds often congregate in large numbers in a particular area, for example roofs and tree branches. There they sing and caw for long periods before taking wing simultaneously until the next congregation. Grackles are cunning and opportunistic birds and are a common sights in towns and hotels throughout Central America. They are omnivorous and brave, often approaching humans in search of scraps of food.
In culture 
In Mexico, where it is known as the Zanate, there is a legend that it has seven songs. "In the creation, the Zanate having no voice, stole its seven distinct songs from the wise and knowing sea turtle. You can now hear the Zanate's vocals as the Seven Passions (Love, Hate, Fear, Courage, Joy, Sadness, and Anger) of life." Mexican artisans have created icons in clay, sometimes as whistles that portray the sea turtle with the Zanate perched on its back. 
- BirdLife International (2012). "Quiscalus mexicanus". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 16 July 2012.
- Powell, A.F.L.A., F.K. Barker and S.M. Lanyon. 2008. A complete species-level phylogeny of the grackles (Quiscalus spp.), including the extinct Slender-billed Grackle, inferred from mitochondrial DNA. Condor 110:718-728.
- "UT's war on grackles". The Daily Texan. Retrieved January 6, 2013.* Hermes JJ (2005). UT's war on grackles. Daily Texan. section. 8A.
- * Wehtje W. (2003). The range expansion of the great-tailed grackle (Quiscalus mexicanus Gmelin) in North America since 1880. Journal of Biogeography. vol 30, no 10. pp. 1593–1607.
Names and Taxonomy
Comments: Formerly considered conspecific with Q. MAJOR, but sympatry without interbreeding known from Louisiana to Texas (AOU 1998). A sister taxon to Q. MAJOR and they probably constitute a superspecies (AOU 1998). See Avise and Zink (1988) for information on genetic divergence between Q. MEXICANUS and Q. MAJOR. See Bjorklund (1991) for a phylogeny of quiscaline icterids based on morphological characteristics. MtDNA data indicate that Q. MAJOR and Q. MEXICANUS are sister taxa (Zink et al. 1991). Often placed in genus Cassidix (AOU 1983).