Calocitta formosawhite-throated magpie-jay

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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, Michoac√°n, 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. (BirdLife International, 2011; Madge and Burn, 1999; Skutch, 1953)

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. (BirdLife International, 2011; Langen and Vehrencamp, 1998; Madge and Burn, 1999; Skutch, 1953)

  • Range elevation
    1,128 (high) m
    ft

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. (Madge and Burn, 1999)

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. (Langen, 1995)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • Range mass
    205 to 213 g
    7.22 to 7.51 oz
  • Average length
    50.8 cm
    20.00 in
  • Range wingspan
    17.8 to 19.3 cm
    7.01 to 7.60 in

Reproduction

White-throated magpie-jays are cooperative breeders, with family members helping a breeding pair to care for and raise young. (Ellis, 2008a; Ellis, 2008b; Langen and Vehrencamp, 1998)

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. (Gray and Del Hoyo, 2009; Innes and Johnston, 1995; Langen, 1996a; Langen, 1996b; Madge and Burn, 1999)

  • Breeding interval
    White-throated magpie-jays generally breed once in the first 4 months of the year, however under circumstances in which the first nest is lost or fails the birds will lay more eggs.
  • Breeding season
    Breeding occurs from January through April.
  • Range eggs per season
    2 to 6
  • Average eggs per season
    3-4
  • Average fledging age
    23 days
  • Range age at sexual or reproductive maturity (female)
    8 to 14 months
  • Range age at sexual or reproductive maturity (male)
    8 to 14 months

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. (Ellis, et al., 2008; Gray and Del Hoyo, 2009; Innes and Johnston, 1995; Langen, 1996a; Langen, 1996b; Madge and Burn, 1999)

  • Parental Investment
  • altricial
  • 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. (de Magalhaes and Costa, 2009)

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. (Gray and Del Hoyo, 2009; Langen, 1995; Madge and Burn, 1999)

  • Average territory size
    0.18 km^2

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. (BirdLife International, 2011; Langen and Vehrencamp, 1998)

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. (Ellis, 2008a; Ellis, 2008b; Ellis, 2010)

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). (Gray and Del Hoyo, 2009; Langen, 1996b)

  • 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. (Ellis, 2010)

Ecosystem Roles

White-throated magpie-jays primary ecosystem role is as seed dispersers. These birds frequently ingest various types of berries, fruits, and seeds. (Gray and Del Hoyo, 2009; Langen and Vehrencamp, 1998; Madge and Burn, 1999)

  • 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. (Ellis, 2008b; Langen, 1996b; Madge and Burn, 1999; Skutch, 1953)

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.

Contributors

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

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

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.

chaparral

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.

chemical

uses smells or other chemicals to communicate

cooperative breeder

helpers provide assistance in raising young that are not their own

diurnal
  1. active during the day, 2. lasting for one day.
ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

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.

female parental care

parental care is carried out by females

iteroparous

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).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

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

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

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

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.

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.