Calocitta formosa

Geographic Range

The range of Calocitta formosa extends southward from Mexico through Central America. They are found in Mexico and the Central American countries of Costa Rica, Guatemala, El Salvador, Honduras, and Nicaragua. The northernmost extent of their range extends to southern Mexican states including Puebla, Colima, Oaxaca, Michoacán, and Chiapas. White-throated magpie-jays are found along the Pacific Coast of Mexico (rather than the Caribbean coast), as they prefer the drier climates found there. The Guanacaste Province of Costa Rica is home to particularly large populations of white-throated magpie-jays and many studies of this species have been conducted there.

• Biogeographic Regions
• nearctic nearctic
  • native native
• neotropical neotropical
  • native native

Habitat

White-throated magpie-jays primarily inhabit drier habitats, particularly dry forests. They are often found in areas of mixed grassland and woodland. They also live in secondary forested areas, near areas under cultivation and along forest edges (particularly pastures consisting of small strips of forests). In addiction, white-throated magpie-jays are often found near clearings and areas of human dwellings and in or near coffee plantations in Central America. This may be due to decreased chance of predation near human settlements. Preferred habitats are generally flat, but these birds also live in hilly areas. Habitat elevation ranges from sea level to approximately 1128 m above sea level.

Most of the vegetation in the habitats of white-throated magpie-jays consists of thorny shrubs and trees, particularly Acacia trees, which are important for feeding in the drier season, and Acrocomina vinifera and Cresenctia alata trees that they use for nesting. Often they choose a relatively isolated tree in the middle of a clearing or pasture for nesting.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• chaparral chaparral
• scrub forest scrub forest

• Other Habitat Features
• agricultural agricultural

Physical Description

White-throated magpie-jays are large, brightly colored birds with long tails and crest feathers. Body weight typically ranges from 205 and 213 g and body length from 46 to 56 cm. Sexual dimorphism is evident in tail length, with females having much shorter tails (267 to 314 mm) than males (284 to 334 mm). Most other male and female body measurements are similar. Wingspan typically ranges from 178 mm to 193 mm. Tarsus length ranges from 39 to 46 mm and bill length from 29 to 34 mm.

Adult white-throated magpie-jays have mostly white face and ventral coloration with rich blue dorsal feathers. Both sexes have a black ring that runs across their breast, beginning behind the eye. Males and females can be distiguished by coloration, with a thinner and often incomplete black ring in males. Males also have partially white crests and very little black coloration above the eye. In contrast, females tend to have almost entirely black crests, and much black or black-and-white mottled coloration above the eye. The auricular patch (patch around the internal ear), is black in both sexes, but much more pronounced in females, often blending into the breast ring.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes colored or patterned differently

Reproduction

White-throated magpie-jays are cooperative breeders, with family members helping a breeding pair to care for and raise young.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)
• cooperative breeder cooperative breeder

White-throated magpie-jays generally breed from January through April. In small groups, one female breeder is typically responsible for incubating all of the eggs, and rarely leaves the nest during this time. Other females bring food to her throughout the incubation process. Males do not play an active role in reproduction, outside of the initial act of fertilizing the eggs.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Young birds are fed in the nest by their mother and other helper females. Females typically stay within the same natal area as they mature, whereas males generally leave the flock either to join another group or to move from group to group.

• Parental Investment
• altricial altricial
• female parental care female parental care
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
• pre-weaning/fledging
  • provisioning
    • female
• post-independence association with parents

Lifespan/Longevity

White-throated magpie-jays are likely to be relatively long-lived. While information on the lifespan of this particular species was not available, it is not uncommon for other species of corvids to live from 15 to 25 years.

Behavior

White-throated magpie-jays have a very large range in Central America, covering vast areas of forests and grasslands. These birds have a complex social structure. White-throated magpie-jays are social birds, living in groups of five to ten. Social groups are comprised primarily of females, that actively defend their territories from other groups. These groups are much more tolerant of males, and will allow "floater males" to associate with the group for an extended period of time. Groups are focused primarily around the breeding female and her offspring, with other birds working as "helpers" to build nests, feed and raise young, and bring food to nesting females. These birds often forage as a group, with fledglings learning from older birds and often taking over foraging sites from their elders. This species is non-migratory, remaining in their territory throughout the year.

• Key Behaviors
• arboreal arboreal
• flies
• diurnal diurnal
• motile motile
• sedentary sedentary
• social social

Home Range

Average territory size ranges from 10 to 27 ha, with an average of approximately 18 ha (based on studies conducted in Parque Nacional Santa Rosa in Guanacaste, Costa Rica). The home range size of "floater males" (those that use or visit multiple territories each day) tends to be much larger than that of a group.

Communication and Perception

White-throated magpie-jays are very vocal, with several different types of calls. Mobbing calls and predator alarms are similar: both consist of a harsh, noisy call that varies in length and rate, depending on the particular threat. In general, the loudest and most vigorous mobbing calls have been noted when nests are approached. Both chicks and adults beg for food, making loud whining vocalizations to entice feeding. Females incubating a clutch will notably beg for up to several hours, and rarely forage during this time. Other social calls include low "chirring", usually produced during mating attempts and during nest-building.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

White-throated magpie-jays are omnivores, feeding primarily on caterpillars and various small fruits. Other food items include grasshoppers and katydids , small lizards, frogs, nestlings of various small birds, and fruits from Acacia trees. Acacia seeds require particular skill to consume, due to the protection of these trees by ant species. Other food items include various large fruits, arthropod egg masses and pupae, wasp nests, and spiders. Diet varies by season, with adult birds consuming mostly fruit during the wet and late wet season (August-December); mostly caterpillars during the early wet season (May-August), and a mixture of miscellaneous small fruit and acacia fruits during the dry season (January-April).

• Primary Diet
• omnivore omnivore

• Animal Foods
• birds
• amphibians
• reptiles
• insects
• terrestrial non-insect arthropods

• Plant Foods
• seeds, grains, and nuts
• fruit

Predation

White-throated magpie-jays protect themselves against predators through their social behavior, including mobbing behavior and alarm calls. Raptor alarm calls are harsh and may vary in intensity given the threat at hand. Raptor alarm calls cause any white-throated magpie-jay nearby to dive for cover. More moderate alarms are called when a bird approaches or when other predators are observed. These birds may even give alarm calls at the site of a car. They also give a loud alarm when a nest is approached by both humans and natural predators, which doubles as a mobbing call.

Ecosystem Roles

White-throated magpie-jays primary ecosystem role is as seed dispersers. These birds frequently ingest various types of berries, fruits, and seeds.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

White-throated magpie-jays seem to have little influence on the human populations around them. White-throated magpie-jays may draw the attention of avid bird watchers, researchers, or tourists and can be seen and studied in Costa Rica's national parks.

• Positive Impacts
• ecotourism ecotourism

Economic Importance for Humans: Negative

White-throated magpie-jays have little negative impact on humans.

Conservation Status

White-throated magpie-jays are found throughout a large range and have large population sizes, so they are evaluated as least concern by the IUCN.

Additional Links

Encyclopedia of Life

Contributors

Tara Paterson (author), Radford University, Melissa Weber (author), Radford University, Christine Small (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Berg, E., J. Eadie, T. Langen, A. Russel. 2009. Reverse sex-biased philopatry in a cooperative bird: genetic consequences and a social cause. Molecular Ecology , 18: 3486-3499.

Berg, E. 2004. A test of sex-ratio biasing in the white-throated magpie-jay, a cooperative breeder with female helpers. The Condor , 106.2: 299-308.

BirdLife International, 2009. " Calocitta formosa " (On-line). IUCN Red List of Threatened Species. Version 2011.1. Accessed February 04, 2011 at http://www.iucnredlist.org/apps/redlist/details/146603/0 .

BirdLife International, 2011. "Species factsheet: Calocitta formosa (white-throated magpie-jay)" (On-line). BirdLife International. Accessed February 04, 2011 at http://www.birdlife.org/datazone/speciesfactsheet.php?id=5720&m=1 .

Ellis, J. 2009. Anti-Predator Signals as Advertisements: Evidence in White-Throated Magpie-Jays. Ethology , 115: 522-532.

Ellis, J. 2008. Which call parameters signal threat to conspecifics in white-throated magpie-jay mobbing calls?. Ethology , 114: 154-163.

Ellis, J., T. Langen, E. Berg. 2008. Signalling for food and sex? Begging by reproductive female white-throated magpie-jays. Animal Behavior , 78.3: 615-623.

Ellis, J. 2010. "White-throated Magpie-Jay" (On-line). Neotropical Birds. Accessed February 20, 2011 at http://neotropical.birds.cornell.edu/portal/species/identification?p_p_spp=514796 .

Ellis, J. 2008. Decay of apparent individual distinctiveness in the begging calls of adult female white-throated magpie-jays. The Condor , 110.4: 648-657.

Gray, G., J. Del Hoyo. 2009. Handbook of the Birds of the World V.14 . Barcelona: Lynx Edicions.

Innes, K., R. Johnston. 1995. Cooperative breeding in the white-throated magpie-jay. How do auxiliaries influence nesting success?. Animal Behavior , 51.3: 519-533.

Langen, T. 1996. Social Learning of a Novel Foraging Skill by White-throated Magpie-jays ( Calocitta formosa , Corvidae) a Field Experiment. Ethology , 102: 157-166.

Langen, T. 1996. Skill acquisition and the timing of natal dispersal in the white-throated magpie-jay. Animal Behaviour , 51: 575-588.

Langen, T. 1995. The mating system of the white-throated magpie-jay Calocitta formosa and Greenwood's hypothesis for sex-based dispersal. Ibis , 138: 506-513.

Langen, T., S. Vehrencamp. 1998. Ecological Factors Affecting Group and Territory Size in White-Throated Magpie-Jays. The Auk , 115/2: 327-339.

Madge, S., H. Burn. 1999. Crows & Jays . Princeton, New Jersey: Princeton University Press.

Skutch, A. 1953. The White-Throated Magpie-Jay. The Wilson Bulletin , 65.2: 68-74.

de Magalhaes, J., J. Costa. 2009. "AnAge: The Animal Ageing & Longevity Database" (On-line). A database of vertebrate longevity records and their relation to other life-history traits. Accessed October 07, 2011 at http://genomics.senescence.info/species/index.html .