Breeding

Many aspects of the Green Jay breeding system vary geographically. The species produces a single brood per year in the northern portion of its range and up to two broods in the south. Nests are built in dense foliage with several supporting branches or near the trunk of a tree. Throughout its geographic range, family flocks retain nonbreeding yearlings until the end of the next breeding season or longer. In Colombia, it is a cooperative breeder, with yearling members feeding nestlings and maintaining the nest site in addition to providing territorial defense (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ). Conversely, Green Jays in southern Texas do not help at the nest but do contribute to territorial defense (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 ). More information on breeding is needed throughout its geographic range.

Pair Formation

Pairs may form at any time of year due to the prolonged absence or disappearance of a breeding member. The exact length of the courtship period before pairing occurs is unknown but breeders will move to other flocks and form new pair bonds in as little as seven days (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Nest Building

The breeding male and female begin nest construction 3–4 weeks before the first egg is laid. The nest is complete 2–7 d before the first egg (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 ).

First Brood

In southern Texas during most years, early nesters lay their first egg in late April (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 clutches are initiated until late June (12 Oberholser, H. C. (1974). The Bird Life of Texas. University of Texas Press, Austin, Texas, USA. Close ); there is a similar phenology in Mexico (103 Sutton, G. M., R. B. Lea, and E. P. Edwards (1950). Notes on the ranges and breeding habits of certain Mexican birds. Bird-Banding 21(2):45–59. Close ). Chicks hatch around 17 d after the first egg is laid (24 Gayou, D. C. (1995). Green Jay (Cyanocorax yncas). In The Birds of North America, No. 187 (A. Poole and F. Gill, Editors), Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC, USA. Close , 16 Roles, D. G. (1971). The breeding Mexican Green Jay at the Jersey Zoological Park. Avicultural Magazine 77:20–22. Close ). Nestlings fledge 19 to 21 d after hatching (24 Gayou, D. C. (1995). Green Jay (Cyanocorax yncas). In The Birds of North America, No. 187 (A. Poole and F. Gill, Editors), Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC, USA. Close ). During mild winters, nesting can occur as early as late January (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 ).

In Colombia, two nesting cycles occur, typically from April to June and October to November. A first clutch can be initiated as early as mid-March. Chicks hatch around 17 d after the first egg is laid. Nestlings fledge 19 to 22 d after hatching but may fledge as early as 17 d (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Second/Later Broods

The Green Jay raises one brood per year in southern Texas (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 up to two broods per year in Colombia (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Selection Process

Both breeding members of the flock participate in site selection, which likely occurs during courtship when the male and female are isolated from yearlings (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Site Characteristics

Nest height varies geographically. In southern Texas and northern Mexico, nests are typically located 2–3 m above ground (range of 0.9–7.6 m; 26 Bent, A. C. (1946). Life histories of North American jays, crows and titmice, Part I. United States National Museum Bulletin 191. Close , 103 Sutton, G. M., R. B. Lea, and E. P. Edwards (1950). Notes on the ranges and breeding habits of certain Mexican birds. Bird-Banding 21(2):45–59. Close , 24 Gayou, D. C. (1995). Green Jay (Cyanocorax yncas). In The Birds of North America, No. 187 (A. Poole and F. Gill, Editors), Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC, USA. Close ). In Colombia, the average nest height is 6.4 m (5.0–10.0 m; 8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Nests are built in dense thickets, trees, and shrubs. In southern Texas, nests are found in a variety of plant species including anacua (Ehretia anacua), brasil (Condalia hookeri), granjeno (Celtis pallida), and Texas ebony (Pithecellobium flexicaule [Ebenopsis ebano]; JCG). In Colombia, Green Jays breeding in pine plantations build nets in patula pine (Pinus patula) and slash pine (Pinus elliottii) trees while jays in secondary forests nest in trees of the genera Alchornea, Myrcia, and Vismia (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Construction Process

The breeding male and female are responsible for the majority of nest construction, carrying and arranging similar amounts of twigs and fine materials (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close , 24 Gayou, D. C. (1995). Green Jay (Cyanocorax yncas). In The Birds of North America, No. 187 (A. Poole and F. Gill, Editors), Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC, USA. Close ). In Colombia, daily nest-building occurs in two periods, between 0700 and 0930 h, and again between 1600 and 1730 h. The breeding pair of the flock initiate nest-building activity by gathering materials in the same area the flock has been foraging. Materials are then carried to the nearby nest site up to 500 m away. Yearling members follow breeders during this process and occasionally participate in nest construction (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Structure and Composition

The nest is a loosely constructed, shallow cup with thin walls. Outer portions are made of thorny twigs and sticks, while the inner cup is made of roots, grass, vines, evergreen needles, moss, and other fine materials (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 ). Eggs are often visible from below (103 Sutton, G. M., R. B. Lea, and E. P. Edwards (1950). Notes on the ranges and breeding habits of certain Mexican birds. Bird-Banding 21(2):45–59. Close , 8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ; JCG). Nests are built on one to several horizontal branches with varying degrees of overhead cover. In Colombia, most nests are located near the trunk of the tree (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Dimensions

External diameter 20–24 cm, external depth 10 cm, inner cup diameter 9 cm, and inner cup depth 5–9 cm (26 Bent, A. C. (1946). Life histories of North American jays, crows and titmice, Part I. United States National Museum Bulletin 191. Close , 8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close , 24 Gayou, D. C. (1995). Green Jay (Cyanocorax yncas). In The Birds of North America, No. 187 (A. Poole and F. Gill, Editors), Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC, USA. Close ).

Microclimate

Little information. The thin walls provide nominal insulation. Nests are usually well-shaded by the forest canopy but some that are built in short vegetation are exposed to the elements (103 Sutton, G. M., R. B. Lea, and E. P. Edwards (1950). Notes on the ranges and breeding habits of certain Mexican birds. Bird-Banding 21(2):45–59. Close , 8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Maintenance or Reuse of Nests

No evidence of alternate nests or nest reuse. Breeding pairs build a new nest each breeding season.

Shape

Oval to short oval (24 Gayou, D. C. (1995). Green Jay (Cyanocorax yncas). In The Birds of North America, No. 187 (A. Poole and F. Gill, Editors), Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC, USA. Close ).

Size

Eggs in the U.S. and Mexico have mean dimensions of 27 mm (range of 25.75–29.68 mm) x 20 mm (range of 19.94–21.26 mm; 26 Bent, A. C. (1946). Life histories of North American jays, crows and titmice, Part I. United States National Museum Bulletin 191. Close , 12 Oberholser, H. C. (1974). The Bird Life of Texas. University of Texas Press, Austin, Texas, USA. Close ; Western Foundation of Vertebrate Zoology). Eggs in Colombia are larger, having mean dimensions of 29.9 mm (range 28.4–31.0 mm) x 22.1 mm (range of 21.5–22.5 mm; 8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Mass

Data only available from eggs in Colombia, which are a mean of 7.7 g (range of 7.1–8.1 g; 8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Color and Surface Texture

Similar across its range, being described as pale gray to greenish white. Dense, dark brown, and lavender spotting present throughout but concentrated near the large end of the egg (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ). Texture is close grained with little gloss (104 Harrison, H. H. (1979). A Field Guide to Western Birds' Nests. Houghton Mifflin Company, Boston, MA, USA. Close ).

Clutch Size

3–4 eggs with ranges from 2 to 6 (103 Sutton, G. M., R. B. Lea, and E. P. Edwards (1950). Notes on the ranges and breeding habits of certain Mexican birds. Bird-Banding 21(2):45–59. Close , 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 , 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 ; Western Foundation of Vertebrate Zoology, JCG). Clutches in southern Texas tend to have 3 eggs, while clutches in Colombia have 4 eggs (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 ).

Egg Laying

Eggs are laid at approximately 24 h intervals (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 ).

Onset of Broodiness and Incubation in Relation to Laying

In clutches of 3 eggs, incubation begins after laying of the second or third egg (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ). In clutches of 4 eggs, incubation begins after the laying of the third egg (16 Roles, D. G. (1971). The breeding Mexican Green Jay at the Jersey Zoological Park. Avicultural Magazine 77:20–22. Close ).

Incubation Patches

Only the females possess a brood patch (24 Gayou, D. C. (1995). Green Jay (Cyanocorax yncas). In The Birds of North America, No. 187 (A. Poole and F. Gill, Editors), Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC, USA. Close ).

Incubation Period

17 d (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 ).

Parental Behavior

Only the female incubates the eggs, sitting tight on the nest, and occasionally rolling eggs throughout the day. The female spends up to 98% of the incubation period attending the nest, only flushing due to large disturbances to the tree or nest site. In one study in Colombia, female recesses lasted between 16 and 81 min, with durations determined by the number of recent feedings by flock members. During recesses, the female briefly perched near the nest and preened before joining the family flock (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Throughout its geographic range, breeding males provide the majority of food to incubating females. In southern Texas, the male feeds the female six or more times per day, sometimes following begging behavior by the female (24 Gayou, D. C. (1995). Green Jay (Cyanocorax yncas). In The Birds of North America, No. 187 (A. Poole and F. Gill, Editors), Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC, USA. Close ). In Colombia, females are occasionally fed by yearling members of the flock. During the end of the incubation period, yearling jays also regularly inspect the nest site, remove debris from the nest cup, and occasionally incubate eggs briefly before being shoved aside by the breeding female (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ). The extent of yearling involvement in parental care during the incubation period is understudied in southern Texas.

Shell Breaking and Emergence

The sequence of hatching appears variable. In Colombia, chicks hatched 1 to 24 h apart (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ). In a captive clutch of four eggs, three chicks hatched during a short period, and the fourth hatched 24 h later (16 Roles, D. G. (1971). The breeding Mexican Green Jay at the Jersey Zoological Park. Avicultural Magazine 77:20–22. Close ).

Parental Assistance and Disposal of Eggshells

After hatching, the breeding female ingests the eggshell fragments (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Condition at Hatching

Altricial, nidicolous, and psilopaedic. Hatchlings are naked, dark-skinned, and blind (17 Friedmann, H. (1925). Notes on the birds observed in the lower Rio Grande Valley of Texas during May 1924. Auk 42(4):538–548. Close , 16 Roles, D. G. (1971). The breeding Mexican Green Jay at the Jersey Zoological Park. Avicultural Magazine 77:20–22. 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 ).

Growth and Development

No data on mass or growth of body parts. Head and spinal tracts become greenish gray, and bluish wing feather quills begin to emerge when chicks are around 4 d old (17 Friedmann, H. (1925). Notes on the birds observed in the lower Rio Grande Valley of Texas during May 1924. Auk 42(4):538–548. Close ). More well-defined feather tracts emerge by day 7 after hatching (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

At 7–8 d old, nestlings stretch their wings and neck frequently and can lift their heads when parents are present. Around 14–15 d old, plumage development accelerates (See Plumages, Molts, and Structure), mobility increases, and nestlings beg with greater strength and fervor (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Brooding

Almost entirely by the female except for brief, infrequent attempts to cover nestlings by the male and yearlings. Females sit loosely during sunny days and fully cover nestlings during strong wind or rain. Other members of the flock frequently guard the nest during female recesses, cleaning the nest cup and remaining at their post despite nearby disturbances. All members remain silent when near the nest. As nestlings age, females feed the young more frequently and spend more time away from the nest. Attentiveness sharply decreases around days 5–6 after hatching. Females spend very little time brooding during the final 3–7 d of the nestling stage and only for long periods when weather is inclement (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Feeding

There are large differences in feeding behavior between northern and southern populations. In southern Texas, yearling jays do not help at the nest, and all food is delivered by the breeding male and female. The male delivers the majority of the food during the first 4–5 d of the nestling period with the female becoming more active after the first week (16 Roles, D. G. (1971). The breeding Mexican Green Jay at the Jersey Zoological Park. Avicultural Magazine 77:20–22. Close , 9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ).

In Colombia, yearling members of the flock act as helpers at the nest, feeding the brooding female or chicks directly. Helpers perform >50% of feeding visits to the nest, but breeding males bring more food per visit. The breeding female spends the first 3–4 d of the nestling period brooding while other members of the flock deliver food to the nest. She then forages and delivers food during the remainder of the nestling period. Feeding rates fluctuate between 3 and 6 visits per hour and increase slightly as the chicks age (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Food items are brought to the nest in the bill and placed directly into the nestling’s gape. When multiple items are being carried, the throat is visibly distended, and additional items may be carried in semi-open bills. In Colombia, food items include insects and small lizards (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ). Stomach content analysis of a young Bronzed Cowbird (Molothrus aeneus) raised by a Green Jay in southern Texas revealed 32% seed material and varying amounts of arachnids, gastropods, hemipterans, lepidopterans, orthopterans, and vermiform larvae in remaining animal material (98 Carter, M. D. (1986). The parasitic behavior of the Bronzed Cowbird in south Texas. Condor 88(1):11–25. Close ). Breeding pairs have been observed delivering cicadas to nestlings (73 Rappole, J. H., S. Glasscock, K. Goldberg, D. Song and S. Faridani. (2011). Range change among New World tropical and subtropical birds. Bonner Zoologische Monographien (57):151-167. Close ).

Nest Sanitation

All members of the family flock contribute to nest sanitation, which primarily occurs after nestlings are fed. Nest attendants swallow fecal sacs produced by chicks during the first seven days of the nestling period. Afterward, sacs are carried and discarded away from the nest; the behavior continues until chicks fledge. During the entire nesting period, attendants also remove dry leaves and sticks that fall into the nest (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Throughout its geographic range, Green Jay family flocks retain nonbreeding yearlings until the end of the next breeding season. In Colombia, Green Jay breeding behavior falls into a strict definition of cooperative breeding, where yearling members feed nestlings and maintain the nest site in addition to providing territorial defense. Additional food provisioning may be the strongest advantage to this system; fledgling survival within flocks was correlated to the number of helpers in a small sample of nests (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

Conversely, Green Jays in southern Texas do not help at the nest but contribute to territorial defense (9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ). All other species that maintain family cohesion but do not cooperatively breed belong to the family Corvidae, including the Eurasian Magpie (Pica pica) , Siberian Jay (Perisoreus infaustus) , and Steller's Jay (Cyanocitta stelleri) (105 Ekman, J. and P. G. P. Ericson. (2006). Out of Gondwanaland: the evolutionary history of cooperative breeding and social behaviour among crows, magpies, jays and allies. Proc. R. Soc. B 273:1117?1125. Close ).

The conditions that lead to the development of cooperative breeding or its absence are heavily debated but variability in habitat quality and food abundance are possible drivers (106 Baglione, V., D. Canestrari, J. M. Marcos, M. Griesser, and J. Ekman (2002). History, environment, and social behaviour: experimentally-induced cooperative breeding in the Carrion Crow. Proceedings of the Royal Society of London 269:1247-1251. Close , 107 Covas, R., C. Doutrelant, and M. A. du Plessis (2004). Experimental evidence of a link between breeding conditions and the decision to breed or to help in a colonial cooperative bird. Proceedings of the Royal Society B: Biological Sciences 271:827-832. Close ). The absence of cooperative breeding in the southern Texas Green Jays may reflect a lack of need for helpers at the nest due to increased availability of food (9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ).

Identity of the Parasitic Species

The Green Jay is a common host of cowbird eggs and young where studied. In southern Texas, the Bronzed Cowbird (Molothrus aeneus) regularly parasitize nests (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 ). In South America, nests are parasitized by the Giant Cowbird (Molothrus oryzivorus) (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 ). While it historically specialized on colonial hosts, the Giant Cowbird is likely parasitizing new host species as it expands its range in Venezuela and Ecuador (108 Welford, M., A. Vásquez, P. Sambrano, T. Nunnery, and B. Ullman (2007). Evidence for Giant Cowbird Molothrus oryzivorus brood-parasitism of Turquoise Jays Cyanolyca turcosa in northwest Ecuador, and how this alters our understanding of cowbird parasitism. Cotinga 27:58-60. 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 ). In newly colonized environments, the Green Jay offers cowbirds an alternative to traditional host species (108 Welford, M., A. Vásquez, P. Sambrano, T. Nunnery, and B. Ullman (2007). Evidence for Giant Cowbird Molothrus oryzivorus brood-parasitism of Turquoise Jays Cyanolyca turcosa in northwest Ecuador, and how this alters our understanding of cowbird parasitism. Cotinga 27:58-60. Close ). Their interactions may be increasing due to destruction and fragmentation of cloud forests (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 ).

Effects of Parasitism on Host

Populations appear stable in areas with high parasitism rates such as Santa Ana National Wildlife Refuge and Bentsen-Rio Grande Valley State Park (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 ). Green Jays may escape some parasitism with early and late nesting seasons.

Departure from the Nest

At around 14 d old, nestlings become more active and move around the nest and nest rim (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 ); they begin to climb adjacent branches at 16–18 d old (24 Gayou, D. C. (1995). Green Jay (Cyanocorax yncas). In The Birds of North America, No. 187 (A. Poole and F. Gill, Editors), Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC, USA. Close ). Nestlings depart the nest at 17–22 d of age and have limited flying capabilities during their first few days after fledging (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 , 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 mean mass of 5 recently fledged birds was 67.9 g (range of 66.0–69.0 g; M. Conway, unpublished data).

Association with Parents or Other Young

Recent fledglings remain close to and beg from the breeding female. In southern Texas, the breeding male rarely associates with the female or fledglings until after the previous year's young are ejected from flock (see Behavior: Social and Interspecific Behavior; 9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ). In Colombia, all members of the flock deliver food to fledglings for at least 20 d after fledging. At 21 d post-fledging, young birds begin to follow flock members and scold predators; despite begging, they receive little food at this point (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ). In Colombia, the young from the previous year appear to remain with the flock for longer periods after the fledglings of the current year leave the nest, but this dynamic is less understood than in southern Texas.

Ability to get Around, Feed, and Care for Self

At 25 d post-fledging, young birds can forage successfully; by 40 d post-fledging, they are able to capture insects as efficiently as yearlings (8 Alvarez, H. (1975). The social system of the Green Jay in Colombia. Living Bird 14:5–44. Close ).

After yearlings have been ejected from the family flock, the current year’s fledglings assume daily foraging activities and territory defense alongside the breeding male and female (9 Gayou, D. C. (1986). The social system of the Texas Green Jay. Auk 103(3):540-547. Close ).