White-throated Magpie-Jay Calocitta formosa

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Behavior

Behavior

Highly social, magpie-jays are rarely encountered as single individuals. They roam through their territories, visiting various fruiting trees and acacias, and taking other prey items as they find them. Social interactions are frequent and important, especially in the breeding season. Dawn finds both paired and unpaired males patrolling territories and home-ranges, flying from tree to tree producing much of their large vocal repertoire. Thereafter social groups begin foraging, but may be visited regularly by floater males. When a jay encounters a predator, active mobbing by the whole group commences, and males may again produce a wide range of sounds.

Territoriality

Territoriality in magpie-jays is complex, due to the complex social structure of these birds. Social groups, which are mostly female, defend territories against other groups; boundary conflicts are marked by sallies and occasional chases, while group members give chirr calls. However, groups not only tolerate floater males, but allow them to associate with groups for long periods, and multiple floaters may be with a single social group at any one time. Only when a breeding female is fertile does her mate defend her.

Territories average approximately 18 ha, ranging from 10 ha to 27 ha in Parque Nacional Santa Rosa in Guanacaste, Costa Rica (Langen & Vehrencamp 1998).

Home ranges of floater males are much larger than group territories; single floater males may visit up to six group territories in a single day (Innes 1992).

Sexual Behavior

When courting, both floater males and paired males may  display to prospective mates. The male will perch alongside a female and sidle up next to her. He then raises his tail at an angle behind him, erects his crest fully, so the plume droops forward, fluffs his neck feathers, and then sidles back and forth on the branch next to her, occasionally switching sides on the branch. During this display he produces a low-amplitude warble than can be highly complex, but is not at all stereotyped. This display (which can also occur in agonistic encounters between males) appears to be part of courtship and perhaps pair-bonding, and is not specifically sexual - that is, copulation does not specifically follow the display.

Females may solicit copulation in the manner of many passerines. They raise their tail and droop their wings, and quiver both. The head may be arched back a little. Copulations are brief.

Social and interspecific behavior

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Recommended Citation

White-throated Magpie-Jay (Calocitta formosa), In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. retrieved from Neotropical Birds Online: https://neotropical.birds.cornell.edu/Species-Account/nb/species/wtmjay1