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| Fig. 1. A pair of adult Javan mynas (Acridotheres javanicus). (Creative Commons License: CC BY-ND 2.0 DE) |
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Introduction
The Javan myna is a conspicuous, vocal, and highly social bird that occurs in a wide range of relatively open habitat, thriving in rural as well as urban settings
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Kang, N., 1989. Comparative behavioural ecology of the mynas, Acridotheres tristis (Linnaeus) and A. javanicus (Cabanis) in Singapore. Unpublished PhD thesis, National University of Singapore, Singapore. |
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Etymology
The generic epithet Acridotheres is derived from the Greek words akrida, meaning a locust, and theres, a hunter, while the specific epithet javanicus is in reference to its native Java
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Pande, S., 2009. Latin names of Indian birds explained. Mumbai: Bombay Natural History Society and Oxford University Press. p. 506. ISBN 978-0-19-806625-5. |
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Identification
From Wells (2009)
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Wells, D. R., 2009. The birds of the Thai-Malay peninsula (Vol. 2). A&C Black. ISBN 978-0-7136-6534-5. |
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unless otherwise stated.
General Identification
Adult Javan myna can be generally identified by the features given in Table 1. Distinctive characteristics for field identification are depicted in the two figures below as well.
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Juvenile Javan mynas tend to be browner, with a very short brown frontal crest. Their underparts appear to be paler and mousier, sometimes with pale feather margins producing a streaky appearance. However, juveniles retain sharply white undertail-coverts very similar to adults. Likewise, the white bases to primaries and tail tip are present in juveniles, but in a narrower band.
Diagnosis
The Javan myna has been readily confused with several species of mynas. Leaving the question of conspecificity with certain other members of genus Acridotheres aside, the Javan myna (A. javanicus) has the following diagnostic characters that best set it apart from other myna species found existing in overlapping or adjacent ranges.
| Fig. 4. Javan myna (Acridotheres javanicus) (Creative Commons License: CC BY-SA 2.0)
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| Fig. 5. Common myna (A. tristis) (Public domain)
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| Fig. 6. Jungle myna (A. fuscus) (Photograph courtesy of Ronnie Ooi)
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| Fig. 7. Great myna (A. grandis) (Photograph by Marco Valentini, permission pending but within Fair Use)
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| Fig. 8. Pale-bellied myna (A. cinereus) (Photograph courtesy of Wong Tsu Shi)
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Vocalizations
Like other Acridotheres mynas, the Javan Myna (A. javanicus) has a varied and strident voice
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| Song | Call |
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Biology
Habitat
The species has been recorded in a wide range of inland man-modified, non-forest habitats, from palm plantations and open agriculture, to parkland, small settlements and suburbia, through to inner-city spaces including fully built-up city centers
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| Fig. 9. The trees lining Orchard Road, Singapore, provide excellent roosts for Javan mynas, many of which have taken up residence to the dismay of retailers and shoppers. (Photograph by Terence Ong) (CC BY-SA 3.0) |
Social Behaviour
Javan mynas are social throughout the year and frequently occur in pairs, which are in turn nested within larger groups, especially when food is abundant or ephemeral
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| Fig. 10. Javan myna perched on dustbin lid in an open air food centre. Javan mynas commonly exploit ephemeral food sources such as food clearing centres in such establishments. (Photo by Gabriel Low) |
Foraging Habits
The Javan myna is an omnivorous bird and is adept at exploiting a wide range of food sources. Their diet is primarily made up of invertebrates, although this is likely dependent on their locality—mynas in a highly urbanized environment may primarily exploit human refuse as a food source (Fig. 10). Javan mynas hunt arthropods and earthworms by probing bare ground or short grass with open bills, even taking Oecophylla weaver ants. They have also been observed aerial foraging for swarming ants and termites, attending oxen for disturbed invertebrate prey, and hunting small crabs on low-tide sand-flats. Javan mynas will take carrion (and the fly maggots found within), as well as fruit and nectar from both cultivated and wild species of plants. Examples include wild figs (Ficus spp.), papaya (Carica papaya), and banana (Musa sp.)
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. Aided by its flexible use of multiple communal roosting sites, Javan mynas are able to make much more efficient use of ephemeral food sources, contributing up to 16% of the intake in the Singapore population.
Breeding Cycle
The Javan myna breeding cycle can be split into three phases: (1) courtship and pair bonding, (2) nesting and incubation, and (3) post-fledging care phases
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. This phase of the breeding cycle usually starts by April and peaks around June.
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Range
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Fig. 11. Distribution of the Javan myna (Acridotheres javanicus) across South-east Asia. Grey circles denote non-captive song recording locations (see section on Vocalizations). Range data originally sourced from BirdLife International and NatureServe (2011). (Adapted from xenocanto.org)
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del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.), 2013. Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. URL: http://www.hbw.com/node/60869. Accessed on 2 November 2014. |
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Distribution and Movement in Singapore and Peninsular Malaysia
The Javan myna was introduced to Singapore in 1924, and its population has since burgeoned to an estimated 122,000 individuals in 2003
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| Fig. 13. Javan mynas perched on a rooftop. The Javan myna is now one of the most human-tolerant birds in South-east Asia, and increasingly posing more of a pest problem. (Photo by Gabriel Low) |
Relationships with Humans
Historically, the Javan myna has been kept in captivity in Malaysia and Indonesia, but thanks to its gregarious, bold nature and its penchant for exploiting human refuse as a food source, its range and abundance has grown dramatically. The Javan myna is now considered a pest by many people. The main cause for concern to most people is their tendency to roost in large communal flocks in close proximity to human-inhabited areas, where their noise and droppings are often complained about (Fig. 13).
However, in Singapore at least, the Javan myna was not always so tolerant of human proximity. Numbers remained low and distribution largely rural prior to WWII, and as recently as the late 1960s, Ward (1968) described these birds as shy birds of the suburbs
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Feare, C. & A. Craig, 1999. Starlings and Mynas. Princeton University Press, New Jersey. 143-145 pp. |
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Taxonomy & Systematics
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| Fig. 14. Screenshot of the original description of the Javan myna published in Museum Heineanum, vol. 1. (Source: Google Book Search) (Public Domain) |
Phylogeny
A hierarchical summary of the taxa within which the Javan myna is placed is provided below:
Animalia
- Chordata
- Aves
- Passeriformes
- Muscicapoidea
- Sturnidae (Rafinesque, 1815)
- Acridotheres (Vieillot, 1816)
- A. javanicus (Cabanis, 1851)
- Acridotheres (Vieillot, 1816)
- Sturnidae (Rafinesque, 1815)
- Muscicapoidea
- Passeriformes
- Aves
Type
The Javan myna (A. javanicus) was originally described by Jean Cabanis in 1851 in Museum Heineanum: Verzeichniss der ornithologischen Sammlung des Oberamtmann Ferdinand Heine 1: 205 (Fig. 14)
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SysTax, 2013. Acridotheres javanicus Cabanis, 1851. Universität Ulm & Ruhr-Universität Bochum. URL: http://www.biologie.uni-ulm.de/cgi-bin/query_all/details.pl?id=116046&stufe=7&typ=ZOO&sid=T&lang=e&pr=nix#herb138591. Accessed on 2 November 2014. |
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Taxonomic Confusion
The Javan myna (A. javanicus) and several other Acridotheres species have often been confused taxonomically, no thanks in part to the inconsistent usage of common names associated with this genus of 'crested' mynas.(4) For example, various authors have referred to A. grandis, A. javanicus, and A. cristatellus as Crested Mynas at different times. The commonly mentioned name White-Vented Myna has also been applied variously to A. javanicus and A. cinereus, and is perhaps most confusing as a name because most Acridotheres mynas possess white vents.
While Cabanis presumably designated the Javan myna as a species of its own based on morphology, various authors have disagreed over time. Amadon (1956) regarded the pale-bellied myna (A. cinereus), the jungle myna (A. fuscus) and the Javan myna as conspecific under A. fuscus
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. Indeed, whereas jungle mynas had been living side by side in Kuala Lumpur with great mynas for almost 20 years without hybridizing, the subsequent introduction of Javan mynas caused a sharp decline in the jungle myna population leading to its local extinction by 2002, all without affecting the great myna population adversely. In the process, suspected jungle-Javan myna hybrids/intergrades were observed at hither-to well known sites for jungle mynas, likely symptoms of the jungle myna population being swamped out genetically by the invading Javan myna.
Phylogenetic Relationships
Genbank has barcode sequences available for several genes including COI, COII, ND2 and Fib5. Sequencing of the full Javan myna genome is underway and should be completed by first quarter 2015 (personal communication).
Usage of molecular phylogenetic methods has led to some level of clarity regarding the Javan myna's relation to other Acridotheres species and it is now clearer that the pale-bellied myna (A. cinereus), the jungle myna (A. fuscus) and the Javan myna (A. javanicus) should all be considered distinct taxa, based on Bayesian inference analysis using mitochondrial ND2 and COII genes (Fig 15.)
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Fig 15. The Bayesian majority rule consensus tree obtained using ND2 and COII mitochondrial genes for the genus Acridotheres. Posterior probabilities equal or higher than 0.95 are indicated at the node. Specimen collection locality is noted next to each individual. The Javan myna's position is indicated by the red line. (Adapted from Zuccon et al., 2008)
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References
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This page was authored by Gabriel Low
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