Behavior

Walking, Running, Hopping, Climbing, etc.

Gayou (5 Gayou, D. C. (1985). The behavioral ecology of Texas Green Jays (Cyanocorax yncas). Ph.D. thesis, University of Missouri, Columbia, Columbia, Missouri, USA. Close ) and Alvarez (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ) provided extensive studies on behavior. The Green Jay hops on the ground and in trees while foraging. Like the Blue Jay (Cyanocitta cristata), it hops rapidly between perches and gives the appearance of a “bouncing” behavior. It flies when disturbed, and it hangs upside down when foraging from slender branches (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Flight

The Green Jay prefers to fly or glide short distances between dense vegetation and thickets. It initially glides after leaving a perch, spreading broad, rounded wings before flapping. It is capable of quick maneuvers and directional changes in flight. It usually avoids flight across large, open areas but its undulating flight pattern resembles woodpeckers when it is forced to cover long distances (5 Gayou, D. C. (1985). The behavioral ecology of Texas Green Jays (Cyanocorax yncas). Ph.D. thesis, University of Missouri, Columbia, Columbia, Missouri, USA. Close ).

Preening, Head-Scratching, Stretching, Sunbathing, Bathing, Anting, etc.

The Green Jay preens throughout day and frequently allopreens during the afternoon. Paired individuals often perch together and exchange contact. Bathing in bird baths or other water sources is followed by extensive preening (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close , 5 Gayou, D. C. (1985). The behavioral ecology of Texas Green Jays (Cyanocorax yncas). Ph.D. thesis, University of Missouri, Columbia, Columbia, Missouri, USA. Close ). In backyards, it uses splash-bathing (i.e., sits on an edge, drinks, and then uses bill to shake water over its body) and immersion-bathing (i.e., stands in shallow water and shakes).

Sleeping, Roosting

Information needed.

Daily Time Budget

Information needed.

Territorial Behavior

Family flocks actively defend established territories and mob conspecific intruders. During an intrusion, members of the flock vocalize loudly and swoop towards the assailant. The breeding male is usually the staunchest defender and is followed by other members. The breeding female rarely participates unless the dispute occurs near the nest. The male interacts by giving continuous Rattle calls while moving its head and body from side to side during territory establishment. Then, while continuing vocalizations, the adversarial males fly toward one another and ascend into a higher perch after each approach (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close , 9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ). The breeding male continues to call and display for several minutes after an intrusion concludes. Intruders that do not vocalize within a territory or interact with family members are usually tolerated (9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ).

Family flocks more actively patrol areas of a territory that are frequently invaded by neighboring flocks. In southern Texas, the intensity of territory defense peaks in March and April when the entire flock moves along territory boundaries and vocalizes frequently. Yearling jays take a prominent roles in territory patrol and defense after nesting is initiated. Yearling flock members were the first to detect intruders in 20 of 31 territorial boundary encounters documented in southern Texas. The breeding male recommits to territory defense alongside yearling members ~4–10 d after new young have fledged (5 Gayou, D. C. (1985). The behavioral ecology of Texas Green Jays (Cyanocorax yncas). Ph.D. thesis, University of Missouri, Columbia, Columbia, Missouri, USA. Close ).

The composition of a family flock remains stable from one breeding season until the end of the next. Flocks consist of a breeding male, a breeding female, and the surviving offspring from previous breeding seasons in winter and spring. Breeding males forcibly drive yearling members from the flock over the course of a 3–5 week period after fledging a new generation of offspring. Initially, the breeding male dives and chases yearlings. Later, the male physically attacks yearlings, leading to animated skirmishes on the ground (9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ).

Mating System and Operational Sex Ratio

Monogamous with cooperative breeding. Yearling offspring from the previous year act as helpers. In southern Texas, helpers assist with territory defense but do not feed nestlings (9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ). In Colombia, helpers assist with both territory defense and nestling feeding (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ; see Cooperative Breeding).

Courtship, Copulation, and Pair Bonds

Breeding pairs rarely part and are often separated from the rest of the family flock to forage or perch. Courtship interactions become more vigorous and frequent as the breeding season approaches. Courtship behavior includes physical bobbing and buzzing calls by females and bill caressing by males. During such interactions, females puff out their body plumage, retract their heads, and give a Rattle call while bobbing up and down. While bobbing, the female extends her legs outward, causing her body to rise; she then lowers herself down until her body almost contacts a branch. The male performs similar behavior, but his body is raised and lowered at a slower rate, often with soft whistles and chirps. The pair repeats this behavior in multiple locations before the female eventually returns to the flock, followed closely by the male. During territorial boundary encounters, the buzzing call and bobbing behavior are given repeatedly and may lead to copulation (16 Roles, D. G. (1971). The breeding Mexican Green Jay at the Jersey Zoological Park. Avicultural Magazine 77:20–22. Close , 8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close , 9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ).

The female frequently begs after the male captures prey items while the pair forages. The female keeps its body low and wings outstretched until the male offers a prey item or departs. Allopreening and body contact while perching is common among paired individuals. It is thought that pairs select potential nest sites during periods of isolation from the flock (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close , 9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ).

Extra-Pair Mating Behavior/Paternity

No evidence of extra-pair mating.

Brood Parasitism of Other Species

No evidence of intraspecific brood parasitism.

Degree of Sociality

The basic social unit is made up of a breeding male and female, accompanied by fledged offspring from the most recent nest attempt. The family flock defends its territory throughout the year with varying levels of tenacity, and yearling birds take more prominent roles in defense during the nesting cycle. The breeding male and female are rarely apart while nesting. When the current year’s young have fledged, the male returns to the yearlings to defend the territory while the female feeds the fledglings.

During the breeding season, yearling members exchange daily “greeting” vocalizations with the breeding pair, consisting of contact calls and Rattle calls while hopping or preening. Greetings from yearlings cease when the current year’s young fledge. During winter, the breeding pair maintains contact but less than during the breeding season. Family flocks reach peak size after the current year’s young have fledged but before the yearlings have left; typical flocks consist of 2–4 yearlings, 3–4 fledglings, and the breeding pair. Shortly after the young have fledged, the breeding male expels the yearlings and reduces the flock size until the next breeding season (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close , 9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ).

Nonpredatory Interspecific Interactions

In southern Texas and Mexico, the Green Jay forages alongside the Altamira Oriole (Icterus gularis) , Couch's Kingbird (Tyrannus couchii), and Golden-fronted Woodpecker (Melanerpes aurifrons)
95 Gehlbach, F. R. (1987). Natural history sketches, densities, and biomass of breeding birds in evergreen forests of the Rio Grande, Texas and Rio Corona, Tamaulipas, Mexico. Texas Journal of Science 39:241–251. Close ). Birds also occasionally follow Plain Chachalaca (Ortalis vetula). There are conflicting reports of Green Jay behavior toward the Bronzed Cowbird (Molothrus aeneus) and the voracity of nest defense may vary locally. Some family flocks regularly chase cowbirds from the nesting area (5 Gayou, D. C. (1985). The behavioral ecology of Texas Green Jays (Cyanocorax yncas). Ph.D. thesis, University of Missouri, Columbia, Columbia, Missouri, USA. Close ) and others do not, resulting in acceptance of cowbird eggs (96 Friedmann, H., L. F. Kiff, and S. I. Rothstein (1977). A further contribution to knowledge of the host relations of the parasitic cowbirds. Smithsonian Contributions to Zoology 235:1–75. Close , 97 Collins, C. T., D. F. Tomback, and G. E. Woolfenden (1980). Additional host records for the Bronzed Cowbird in Texas. Bulletin of the Texas Ornithological Society 13:50–51. Close , 98 Carter, M. D. (1986). The parasitic behavior of the Bronzed Cowbird in south Texas. Condor 88(1):11–25. Close ). The utility of nest defense against cowbirds may depend on several factors (see Breeding).

In South America, there is no obvious formation of mixed species foraging flocks, but it is occasionally associated with the Golden-olive Woodpecker (Colaptes rubiginosus). The Giant Cowbird (Molothrus oryzivorus) regularly follows Green Jay family flocks, but is usually met with disinterest outside of the breeding season. Multiple members of the flocks chase away cowbirds that venture near active nests, sometimes joined by the brooding female. Cowbirds remain bold despite Green Jay defensive behavior and occasionally successfully parasitize nests (99 Lehmann, F .C. (1960). Contribuciones al estudio de la fauna de Colombia. XV. Novedadas Colombianas 1:256-276. Close , 8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close , 100 Ramoni-Perazzi, P., G. Bianchi-Ballesteros, L. D. Otero, A. Soto-Werschitz, and G. Bianchi-Pérez (2010). Giant Cowbird (Molothrus oryzivora) as brood-parasite of the Green Jay (Cyanocorax yncas) in the Venezuelan Andes. Ornitología Neotropical 20: 305-309. Close ; see Breeding).

Kinds of Predators

Free-ranging domestic cats kill between 1.3 and 4 billion birds annually in the U.S. (101 Loss, S. R., T. Will, and P. P. Marra (2013). The impact of free-ranging domestic cats on the wildlife of the United States. Nature Communications 4:1396. Close ) and certainly depredate the Green Jay throughout its range. Three dead recoveries of banded Green Jays in southern Texas were attributed to cats (88 Bird Bandling Lab (2022). North American Bird Banding Program Dataset 1960–2022 retrieved 2022-07-14. (A. Celis-Murillo, M. Malorodova, E. Nakash, Editors). Eastern Ecological Science Center, Kearnyville, WV, USA. Close ).

Falcons and small raptors are plausible natural predators (81 Brush, T. (2005). Nesting birds of a tropical frontier: the lower Rio Grande Valley of Texas. College Station, TX: Texas A&M University Press. Close ). The Sharp-shinned Hawk (Accipiter striatus) is thought to be a common predator of adult birds. The Smooth-billed Ani (Crotophaga ani) has been documented depredating eggs in Colombia (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Response to Predators

The Green Jay enthusiastically scolds human intrusions into its territories (5 Gayou, D. C. (1985). The behavioral ecology of Texas Green Jays (Cyanocorax yncas). Ph.D. thesis, University of Missouri, Columbia, Columbia, Missouri, USA. Close ). Loud vocalizations are used by family flocks to signal the presence of avian predators. Unprovoked mobbing of raptors is common, and jays sometimes drive predators completely away from areas (81 Brush, T. (2005). Nesting birds of a tropical frontier: the lower Rio Grande Valley of Texas. College Station, TX: Texas A&M University Press. Close ). If mobbing and scolding is ineffective, Green Jays can knock predators from perches and continue pecking on the ground below (102 Proudfoot, Glenn A. and R. Roy Johnson. (2000). Ferruginous Pygmy-Owl (Glaucidium brasilianum), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA. Close ). In response to Sharp-shinned Hawk attacks, jays congregate in dense cover and return attacks with pecks from below or above (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ). In Colombia, Green Jays will attack nearly any species that comes near their nest, including the Great Thrush (Turdus fuscater) , Squirrel Cuckoo (Piaya cayana) , Yellow-billed Cuckoo (Coccyzus americanus) , and Amazonian Motmot (Momotus momota) (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).