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Haemig PD (2011) Ecology of the Brown Jay. ECOLOGY.INFO 21

Ecology of the Brown Jay

Note: This online review is updated and revised continuously, as soon as results of new scientific research become available.  It therefore presents state-of-the-art information on the topic it covers.

Along the Atlantic slope of Mexico and Central America, few birds are more familiar to the average person than the Brown Jay (Psilorhinus morio).  Conspicuous in villages, farmlands, banana plantations and in vegetation alongside roads, the Brown Jay is characteristic of disturbed habitats and second-growth woodlands throughout the tropical lowlands, and in some highland areas as well.

Because it is bold, conspicuous, large in size, and its nests are easier to find than those of other tropical birds, the Brown Jay is a good species with which to study general questions of ecology and behavior.  For the same reasons, it is also a good species for student projects.  In this review, we summarize all that is currently known about the ecology of the Brown Jay.

Distribution and Abundance

The Brown Jay ranges from the lower Rio Grande Valley of Texas south to Panama.  It is confined almost entirely to the Atlantic Slope of Middle America, however in parts of Costa Rica its range also extends over onto the Pacific Slope (Phillips 1986).

In most areas where it is found, the Brown Jay seems to be more abundant today than in the past.  The reason for this increased abundance is that the extensive tropical forests of Mexico and Central America, which the Brown Jay avoids, have largely been cleared and replaced by farms, plantations and various second-growth habitats in which this bird thrives (Skutch 1960).

As the Brown Jay population has grown, new areas have been colonized, expanding the range of this species.  For example, at Monteverde on the Pacific slope of Costa Rica, Brown Jays were unknown before 1960 (W. Guindon in Williams et al. 1994).  Shortly after this time, however, they colonized the area and within thirty years became very abundant (Williams et al. 1994).

Elsewhere, the Brown Jay is extending its range south into central Panama (Lawton 1983).  Williams and Lawton (2000) suggest that the Brown Jay's habit of living in groups helps it to colonize new areas, because "group living potentially lowers predation risk" and "gives an advantage in inter-specific competition for food and nest sites." 

Nevertheless, while the above examples show that the Brown Jay is successfully expanding its range in some areas, such has not always been the case.  In the far north of its range, i.e. Texas, the Brown Jay has become extinct in at least one area where it formerly occurred (see next section).

Texas Brown Jays

In the United States, the Brown Jay is found only in the lower Rio Grande Valley of Texas.  There, it is a "rare to uncommon and very local resident along the Rio Grande in Starr County, between Rio Grande City and San Ygnacio [Zapata County] (Texas Ornithological Society 1995)." 

There is good evidence, however, that the Brown Jay formerly bred in other parts of the lower Rio Grande Valley of Texas, specifically in the Rio Grande Delta.  Two specimens of the Brown Jay from Cameron County, 150 kilometers east of its present range, have been found in the collections of the Delaware Museum of Natural History (Hubbard and Niles 1975).  The first is an immature male collected at Brownsville on 27 February 1897; the second is a clutch of 6 eggs collected at Brownsville on 25 April 1900.  The eggs were taken from a Brown Jay nest constructed of twigs in a "small tree in big woods near town, 14 feet from [the] ground (Hubbard and Niles 1975)."  The large number of eggs collected from this nest suggests that more than one female laid eggs in it.  Such communal egg-laying by the Brown Jay has been documented by Lawton and Lawton (1985) at Monteverde, Costa Rica (see below).

Voice

One reason the Brown Jay is so conspicuous is that it is loud and noisy.  Flock members call loudly to each other throughout the day.  They also boldly investigate intruders and give warning calls that alert other bird species of danger.  Skutch (1960) writes:

"Brown Jays are restless, active birds.  Their calls are heard in the morning almost before the human eye can detect the lifting of the night, except perhaps the faintest brightening of the sky low in the east.  In the hot middle of the day, when other lowland birds are resting silent and unseen in the shade, they seem to go out of their way to protest a man's passage through their haunts.  They are among the last of the diurnal birds to settle to roost in the evening.  They forage usually in small, loose flocks of from six to ten individuals, and it is difficult to elude so many keen eyes and to watch these birds unobserved.  One of the party is sure to spy you, and his persistent chaa chaa of alarm sends sends off the whole flock with loud protesting cries.  I have sometimes had the annoying experience, while sitting quietly in my blind before the nest of a pair of birds of another species which were oblivious to my presence, of having a Brown Jay perch somewhere above me and scold persistently in raucous tones.  At times this action would arouse the suspicions of the birds I was watching, and I longed to emerge from my hiding place and throw something at the inconsiderate alarmist.  Whether its restless eyes caught mine through the peephole, or whether the blind itself was the cause of its scolding, I could not always decide.  Bird collectors [that work at museums] wax eloquent when describing the annoyance which the jay causes them, for it is keen to detect their approach and broadcasts the news to all the feathered world.

While walking through the banana groves, I often encountered Brown Jays.  They either fled away with harsh complaints or one would linger upon the petiole of a banana leaf, watching me approach as it bowed excitedly first to the right and then to the left.  With each forward movement of its body, it uttered a noisy scold with the utmost vehemence and with such rapidity that its loud chaa's seemed to stumble over each other in its windpipe and to choke it.  The scolds were punctuated by a note somewhat resembling the sound made by pulling a cork from a vial.  At length, as I pushed closer than the jay deemed safe, it would take wing, and in a moment it would be hidden by the huge foliage."1

The sound that Skutch says resembles the pulling of a cork from a vial is called a "hiccup" by some authors, however this name is not completely satisfactory.  According to Sutton and Gilbert (1942), the "hiccup" resembles the syllables "puck or huck" and has a "snapping or popping quality."  It is produced not by the Brown Jay's syrinx, but by its furcular pouch, a unique structure resembling a crop that is connected to the bird's interclavicular air sac (Sutton and Gilbert 1942).  This pouch is located on the Brown Jay's chest, but is usually hidden from view by the throat and breast feathers (Sutton and Gilbert 1942).  The Brown Jay is the only species of the bird family Corvidae that possesses a furcular pouch, and both sexes, as well as juveniles, have it (Sutton and Gilbert 1942). 

Noisy at the Nest

Brown Jays differ from most other tropical land birds in that they are "conspicuous and noisy while breeding" (Lawton and Lawton 1980; Ellis et al. 2009).  Throughout nest-building and incubation, Brown Jays spend long periods whining loudly from their nests.  These noisy calls make it easy for researchers to find Brown Jay nests.  Skutch (1960) writes:

"On 'Alsacia' Plantation in the Motagua Valley [Guatemala], in April and early May when the Brown Jays' season of incubation was at its height, I heard their peculiar loud cries arising from all the busy hillsides and vine-entangled bottom lands, where isolated trees remained to support the nests.  Following these sounds, it was easy to locate them; there are few birds whose nests are found more readily that those of the Brown Jay.  Individual hens differed in their noisiness, some being exceedingly vociferous, other comparatively silent.  I counted the calls of an unusually clamorous female which was incubating in a tall tree beside a brook.  In two minutes she called from the nest thirty times, and when hungry she continued at this rate for many minutes together, until at last her negligent mate came to give her food and stand guard while she hunted more."1

These loud nest calls begin even before incubation, allowing researchers to locate the nest while it is being built.  Skutch (1960) writes:

"In the Brown Jay, nest building, like most other activities, is a noisy performance.  As soon as the site has been selected, or at least as soon as the first stick is laid, the birds sit in it and continually utter loud, mournful cries which carry for long distances.  This loud, sad pee-ah, very different in quality from the ordinary calls of the jay, is heard almost exclusively from nesting birds and from fledglings begging for food.  Following it to its source, I found all the nests of which I watched the construction.  Male and female unite in the labor, as is usual in the Corvidae.  In some pairs they share the work nearly equally, while in other pairs the female seems to perform the larger part of the task of building.  After adding a stick to the growing pile and shaping it with depressed breast and active feet, she remains sitting in the incipient structure, uttering her plaintive calls, until her mate comes near with his contribution.  Then she makes way for him, perhaps going off to find another stick, while he deposits his and sits in the nest to shape it, often crying, but usually he does not sit as long or cry as loudly as his mate.  Sometimes, however, either member of the pair may work in the complete   absence of the other."1
 

Cooperative Breeding and Communal Egg-laying

Brown Jays live in groups.  During the breeding season these groups consist of 3 to 17 individuals (Lawton and Lawton 1985; Williams et al. 1994).  Each group is composed of breeding and non-breeding individuals that defend a common territory.  Non-breeding individuals help the breeding individuals "build nests; feed breeding females, nestlings and fledglings; and defend the nest from predators (Williams and Lawton 2000)."  So far, no ornithologist has ever observed a simple pair of Brown Jays nesting without the assistance of non-breeding individuals (Williams 2004).

This kind of breeding system, where non-breeding members of a group help raise young that are not their own, is called "cooperative breeding."  The non-breeding individuals that assist the breeding individuals are called "helpers."

It is not unusual for young Brown Jays to work as "helpers" for many years before themselves breeding (Williams and Lawton 2000; Williams and Dale 2006, 2007, 2008).  These young Brown Jays benefit from helping because it gives them experience "learning how to build nests and take care of young (Williams and Lawton 2000)."

Lawton and Guindon (1981), for example, found that young Brown Jay helpers showed improvement in the care they provided to nestlings over just one nesting period.  Years later, when they mature and breed, these jays will be better able to do so because of the experience they gained as "helpers" during previous years.  Older experienced individuals enhance the breeding success of flocks because they are the most efficient nest attendants (Lawton and Guindon 1981).  The number of flock members 4 years of age or older is a much better predictor of breeding success than the number of individuals in a flock (Lawton and Guindon 1981).  At Monteverde, Costa Rica, Brown Jay groups usually "contain two to five females and two to nine males that are older than 2 years of age (Williams 2004)." 

At Monteverde, Brown Jay young "remain on their natal territories through their first year and most (90%) remain through their second year (Williams 2004)."  After the second year, 84% of females continue to live on their natal territories, however about half of the males disperse to find new groups to live with (Williams 2000). 

At Monteverde, researchers have found great diversity in Brown Jay groups with regards to breeding.  Some groups have only one breeding female and hence only one nest; other groups have two or three breeding females, each with their own nest; while still other groups have two or more females that lay eggs in a single nest (Williams and Lawton 2000).  The latter situation is called "communal egg-laying."  Although not common among other birds, cooperative breeding and communal egg-laying are found in some other Neotropical birds.  Perhaps the best known are the 3 species of anis (Crotophaga spp.).

Nest-site Selection

The Brown Jay builds its nest in trees.  Skutch (1960) describes the nest tree as follows: "A tree of moderate height standing alone in a pasture, or rising above the bushes and vine tangles of recent second growth, is most favored.  Here the nest is almost always supported among the twigs at the end of a long slender branch...25 to 50 feet above the ground.1"

At Monteverde, Costa Rica, Lawton and Lawton (1980) studied nest tree selection by Brown Jays.  They found that the nest trees selected maximized protection from two dangers: (1) predators that plunder nests to eat eggs and young, and (2) strong winds that blow nests out of trees.

Like Skutch (1960), the Lawtons found that Brown Jays usually nested in isolated trees rather than in trees growing in patches of forest or windbreaks.  Because the few nests built in trees with crowns touching other trees were all destroyed by nocturnal predators, while most nests placed in isolated trees were not destroyed by predators, the Lawtons believed that Brown Jays nested in isolated trees to obtain greater protection from nocturnal arboreal predators. 

A drawback to nesting in isolated trees, however, is that they are often exposed to stronger winds than trees growing in a forest patch or windbreak.  Fortunately, the topography at Monteverde is varied, so some isolated trees are sheltered from strong winds by ridges and hills.  Consequently, the Lawtons found that Brown Jays at Monteverde built most of their nests in isolated trees that were more protected from the wind than a random sample of isolated trees."

Food Habits and Seed Dispersal

Like most other members of the Crow family (Corvidae), the Brown Jay is omnivorous.  However, the largest part of its adult diet is made up of wild fruits of which it eats many species (Skutch 1960; Cant 1979; Wheelwright et al. 1984; Bronstein and Hoffmann 1987).

Like other large-bodied fruit-eating birds, such as Guans (Penelope spp.), Chachalacas (Ortalis spp.), Quetzals (Pharomachrus spp.) Bellbirds (Procnias spp.), Cock-of-the-Rock (Rupicola spp.) and Toucans (Ramphastidae spp.), the Brown Jay is an important long-distance disperser of seeds.  For example, in the lowland tropical rainforest of the Sierra de los Tuxtlas, Mexico, Coates-Estrada and Estrada (1988) studied the role that frugivorous birds (including the Brown Jay) play in dispersing seeds of Cymbopetalum bailloni, a medium-sized tree (up to 20 meters high) with oil-rich arils.  Although 23 other species of birds also consumed the fruits of this tree, the Brown Jay was the most important long-distance disperser of its seeds, accounting for 46% of all Cymbopetalum bailloni seeds dispersed more than 30 meters from the parent tree.  In contrast, the next most important long-distance disperser of Cymbopetalum bailloni seeds, the Rainbow-billed Toucan (Ramphastos sulfuratus), accounted for only 16%.  Seed dispersal was by regurgitation rather than defecation.

Association with Army Ants

In a second-growth tropical deciduous forest along the Rio Sabinas in southern Tamaulipas, Mexico, Haemig (1989) found Brown Jays associating with swarms of army ants (Eciton burchelli).  He observed six Brown Jays, two Melodious Blackbirds (Dives dives) and one Ivory-billed Woodcreeper (Xiphorynchus flavigaster) following a small army ant swarm for more than 2 hours as it moved slowly through the forest.  During this time, the Brown Jays, blackbirds and woodcreeper fed on various arthropods and other small animals that fled cover to escape the advancing ants. 

Shifts in Foraging

In Tamaulipas and San Luis Potosi, Mexico, the average height at which Brown Jays forage in trees decreases as the morning progresses and the sun rises higher in the sky (Morrison and Slack 1977). Possible reasons for this decrease in foraging height include: 1) The jays are forced down into shaded areas below the canopy of the trees in order to avoid thermal stress from the hot sun, 2) small animals eaten by the jays move to lower heights in the trees as the day progresses and the jays follow them, and 3) the jays are simply moving to a preferred foraging zone after initially rallying in the canopy of the trees (Morrison and Slack 1977).

Enemies

At Tikal National Park, Guatemala, Thorstrom (2000) found the Collared Forest-Falcon (Micrastur semitorquatus) preying upon the Brown Jay.  At Monteverde, Costa Rica, Lawton and Lawton (1980) observed flocks of nesting Brown Jays drive away the following predators:

Broad-winged Hawk (Buteo platypterus)
Common Black Hawk (Buteogallus anthracinus)
Red-bellied Squirrel (Sciurus variegatoides)
White-faced Monkey (Cebus capucinus)
Domestic Cat (Felis catus)

Systematics and Nomenclature

The Magpie Jays (Calocitta formosa and Calocitta colliei) are considered to be the sister group of the Brown Jay and are its closest phylogenetic relatives (Saunders and Edwards 2000).  Because Magpie Jays inhabit the Pacific Slope of Middle America and Brown Jays the Atlantic Slope, the two kinds of jays have generally separate ranges and replace each other geographically.  However, in some areas, Brown Jays and Magpie Jays come in contact with each other and interact.  For example, in Costa Rica, where the Brown Jay's range extends onto the Pacific Slope, White-throated Magpie Jays (Calocitta formosa) are sometimes seen flocking with Brown Jays (Lawton 1983), and, in Chiapas, Mexico, a hybrid of the two species has been collected (Pitelka et al. 1956).

Some taxonomists have placed the Brown Jay in the genus Cyanocorax instead of Psilorhinus (Bonoccorso et al. 2010).  However, the DNA evidence just mentioned suggests that the Brown Jay lies outside the Cyanocorax clade and closer to its sister group the Magpie Jays.  Saunders and Edwards (2000) write, "the case of Psilorhinus represents a good example of the possible paraphyly of genera erected on morphological grounds and in the absence of tree thinking by traditional alpha-taxonomy, which naturally assumes each named genus (sensu lato) to be monophyletic."

Throughout its extensive range, the Brown Jay is known by many different vernacular names.  In Mexico and northern Central America, the following names are used:  papán, chara parda, papán mexicano, papán moreno, papán oscuro, pea, pepe, shara, urraca chillona (Schoenhals 1988).  In Costa Rica, the Brown Jay is called piapia (pronounced "piá-piá" Skutch 1960).  Many of these names, such as pea, piapia, and papán, appear to be onomatopoeic, i.e. imitations of the vocalizations made by the Brown Jay.

Footnotes

1.  Four paragraphs quoted from Skutch (1960) are reprinted with permission of the Cooper Ornithological Society. 

References

Bonaccorso E, Peterson AT, Navarro-Siguenza AG, Fleischer RC  (2010)  Molecular systematics and evolution of the Cyanocorax jays.  Molecular Phylogenetics and Evolution 54: 897-909

Bronstein JL, Hoffmann K  (1987)  Spatial and temporal variation in frugivory at a Neotropical fig, Ficus pertusaOikos 49: 261-268

Cant JGH  (1979)  Dispersal of Stemmadenia donnell-smithii by birds and monkeys.  Biotropica 11:122

Coates-Estrada R, Estrada A  (1988)  Frugivory and seed dispersal in Cymbopetalum baillonii (Annonaceae) at Los Tuxtlas, Mexico.  Journal of Tropical Ecology 4: 157-172

Ellis JMS, Langen TA, Berg EC  (2009)  Signalling for food and sex?  Begging by reproductive female white-throated magpie-jays.  Animal Behaviour 78: 615-623

Haemig PD  (1989)  Brown Jays as army ant followers.  Condor 91: 1008-1009

Hale AM, Williams DA, Rabenold KN  (2003)  Territoriality and neighbor assessment in Brown Jays (Cyanocorax morio) in Costa Rica.  Auk 120: 446-456

Hubbard JP, Niles DM  (1975)  Two specimen records of the Brown Jay from southern Texas.  Auk 92: 797-798

Lawton MF  (1983) Cyanocorax morio (Urraca Parda, Piapia, Brown Jay).  Pp. 573-574 in Costa Rican Natural History (Janzen DH, editor), University of Chicago Press.

Lawton MF, Guindon CF  (1981)  Flock composition, breeding success and learning among Brown Jays.  Condor 83: 27-33

Lawton MF, Lawton RO  (1980)  Nest-site selection in the Brown Jay.  Auk 97: 631-633

Lawton MF, Lawton RO  (1985)  The breeding biology of the Brown Jay in Monteverde, Costa Rica.  Condor 87: 192-204

Morrison ML, Slack RD  (1977)  Flocking and foraging behavior of Brown Jays in northeastern Mexico.  Wilson Bulletin 89: 171-173

Phillips AR  (1986)  The Known Birds of North and Middle America, Part 1.  ARP, Denver

Pitelka FA, Selander RK, Alvarez del Toro M  (1956)  A hybrid jay from Chiapas, Mexico.  Condor 58: 98-106

Romero-Balderas KG, Naranjo EJ, Morales HH, Nigh RB  (2006)  Damages caused by wild vertebrate species in corn crops at the Lacandon Forest, Chiapas, Mexico.  Interciencia 31: 276-283

Saunders MA, Edwards SV  (2000)  Dynamics and phylogenetic implications of MtDNA control region sequences in New World Jays.  Journal of Molecular Evolution 51: 97-109

Schoenhals LC  (1988)  A Spanish-English Glossary of Mexican Flora and Fauna.  Summer Institute of Linguistics, México, DF

Skutch AF  (1960)  Life Histories of Central American Birds. II.  Pacific Coast Avifauna 34: 231-257

Sutton GM, Gilbert PW  (1942)  The Brown Jay's furcular pouch.  Condor 44: 160-165

Texas Ornithological Society  (1995)  Checklist of the Birds of Texas.  Third Edition.

Thorstrom R  (2000)  The food habits of sympatric forest-falcons during the breeding season in northeastern Guatemala. Journal of Raptor Research 34: 196-202

Wheelwright NT, Haber WA, Murray KG, Guindon C  (1984)  Tropical fruit-eating birds and their food plants: a survey of a Costa Rican lower montane forest.  Biotropica 16: 173-192

Williams DA  (2004)  Female control of reproductive skew in cooperatively breeding Brown Jays (Cyanocorax morio).  Behavioral Ecology and Sociobiology 55: 370-380

Williams DA, Lawton MF, Lawton RO  (1994)  Population growth, range expansion, and competition in the cooperatively breeding Brown Jay, Cyanocorax morioAnimal Behaviour 48: 309-322

Williams DA, Lawton MF  (2000)  Brown Jays: complex sociality in a colonizing species.  Pp. 212-213 in Monteverde: Ecology and Conservation of a Tropical Cloud Forest.  Nadkarni NM, Wheelwright NT (editors).  Oxford University Press, New York

Williams DA, Rabenold KN  (2005)  Male-based dispersal, female philopatry, and routes to fitness in a social corvid.  Journal of Animal Ecology 74: 150-159

Williams DA, Hale AM  (2006) Helper effects on offspring production in cooperatively breeding Brown Jays (Cyanocorax morio).  Auk 123: 847-857

Williams DA, Hale AM  (2007)  Female-biased helping in a cooperatively breeding bird:  Female benefits or male costs?  Ethology 113: 534-542

Williams DA, Hale AM  (2008)  Investment in nesting activities and patterns of extra- and within-group genetic paternity in a cooperatively breeding bird.  Condor 110: 13-23

Information about this Review

This review is also available in the following languages:  

Spanish

The author is:  Dr. Paul D. Haemig (PhD in Animal Ecology)

Photograph:  Brown Jay, Monteverde, Costa Rica, by Jim Scarff (USA).

The proper citation is:

Haemig PD  2012   Ecology of the Brown Jay.  ECOLOGY.INFO  #21

If you are aware of any important scientific publications about the Brown Jay that were omitted from this review, or have other suggestions for improving it, please contact the author at the following e-mail address: 

director {at} ecology.info 

The author thanks Dr. John H. Rappole for advice in writing this review.

© Copyright 2003-2012 Ecology Online Sweden.  All rights reserved.

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