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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.).
Footnote Macro

Kang, N., 1992. Radiotelemetry in an urban environment: a study of Mynas (Acridotheres spp.) in Singapore. Pp 633—641 in Priede, I.G. & S.M. Swift (eds.), Wildlife telemetry, Remote monitoring and tracking of animals. Ellis Horwood, Chichester.

 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 phase.
Footnote Macro

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 Unpublished PhD thesis, National University of Singapore, Singapore.

 While breeding occurs throughout the year and does not start with the beginning of a calendar year, peaks in each of the three phases occur over the course of the year.

Courtship and Pair Bonding

Javan myna courtship activities include fighting and fencing, as well as bowing courtship displays with vocalizations.
Footnote Macro

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 Unpublished PhD thesis, National University of Singapore, Singapore.

However, these activities are not entirely distinct from their usual maintenance behaviours and displays. This phase of the breeding cycle usually starts in August and peaks in December.

Nesting and Incubation

Javan mynas nest sites include palm fruit clusters amid palm crowns and holes in tall trees, buildings, bridges, and other manmade structures.
Footnote Macro

Feare, C. & A. Craig, 1999. Starlings and Mynas. Princeton University Press, New Jersey. 143-145 pp.

 A clutch of 2–5 plain pale blue eggs are usually laid and incubated for 13–14 days. This phase of the breeding cycle usually starts by January and peaks in March 
Footnote Macro

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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Post-fledging Care
Juvenile Javan mynas will follow their parents and beg to be fed 
Footnote Macro

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.

This phase of the breeding cycle usually starts by April and peaks around June.

Range

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)

Footnote Macro

Xeno-canto Foundation, 2014. Javan myna, Acridotheres javanicus, Cabanis 1851. Hosted on Xeno-canto.org. URL: http://www.xeno-canto.org/species/Acridotheres-javanicus. Accessed on 11 November 2014.


The Javan Myna’s range has not been assessed comprehensively, in part hampered by controversy regarding its taxonomy. However, it is generally agreed to be indigenous to Java and Bali, and subsequently introduced to Sarawak, Sumatra, Singapore, Peninsular Malaysia, the Lesser Sundas, and Myanmar within Southeast Asia (Fig. 11).

Footnote Macro

Wells, D. R., 2009. The birds of the Thai-Malay peninsula (Vol. 2). A&C Black. ISBN 978-0-7136-6534-5.

Footnote Macro

Feare, C. & A. Craig, 1999. Starlings and Mynas. Princeton University Press, New Jersey. 143-145 pp.

Footnote Macro

Yap, C.A.M. & N.S. Sodhi, 2002. Roost characteristics of invasive mynas in Singapore. Journal of Wildlife Management 66: 1118–1127.


Elsewhere, it has also been introduced to Christmas Island, Taiwan, and Puerto Rico
Footnote Macro

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.

Footnote Macro

Lim, H.C., N.S. Sodhi, B.W. Brook & M.C.K. Soh, 2003. Undesirable aliens: Factors determining the distribution of three invasive bird species in Singapore. Journal of Tropical Ecology19(6): 685–695.

 In 2012, a study at the National University of Singapore utilized survey data by Wang Luan Keng to analyze the distribution of roosts in urban areas across the island using a GIS statistical package.

Footnote Macro

Boo, J.T.C., K.E. Ong, X.R. Ong & E.J.Y. Soh, 2013. Spatial distribution of Javan mynas in Singapore.Unpublished GE3238: GIS Design and Practices project report. National University of Singapore. Singapore, 87pp.

 Their reconstructed Javan myna roost distribution can be seen in Figure 12 below.


Fig. 12. Javan myna roost locations in Singapore in 2012, with total range buffer (radius=990.14m) superimposed and colored to show spatial clustering of mynas. Pink dots represent large roosts (>50 birds) while blue dots represent small roosts (<50 birds). Place names are labeled accordingly. (Adapted from Boo et al., 2013)

Footnote Macro

Boo, J.T.C., K.E. Ong, X.R. Ong & E.J.Y. Soh, 2013. Spatial distribution of Javan mynas in Singapore.Unpublished GE3238: GIS Design and Practices project report. National University of Singapore. Singapore, 87pp.

 (Data used for map construction is copyrighted. Permission must be sought before reuse)


Using radio-tagging, Javan mynas have been shown to move an average of 1.6km between feeding spaces and roosts.

Footnote Macro

Kang, N., 1992. Radiotelemetry in an urban environment: a study of Mynas (Acridotheres spp.) in Singapore. Pp 633—641 in Priede, I.G. & S.M. Swift (eds.), Wildlife telemetry, Remote monitoring and tracking of animals. Ellis Horwood, Chichester.

 Additionally, thousands of Javan mynas have been observed commuting at dawn over the Johor straits to foraging areas in mainland Johor, possibly beyond Johor Bahru town.

Footnote Macro

Wells, D. R., 2009. The birds of the Thai-Malay peninsula (Vol. 2). A&C Black. ISBN 978-0-7136-6534-5.

 With the Johor straits being 600m at its narrowest, Javan myna invasion of the Malay Peninsula mainland would have inevitably involved establishment of such commuters on the Johor side of the straits, and their subsequent northward spread.


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.

Footnote Macro

Ward, P., 1968. Origin of the avifauna of urban and suburban Singapore. Ibis 110: 239–254.

Indeed, it was the common myna (Acridotheres tristis) that was the dominant myna species in Singapore for a long time. However, with increasing urbanization, Hails found in 1985 that Javan mynas outnumbered common mynas by 2.7 times 

Footnote Macro

Hails, C.J., 1985. Studies on problem bird species in Singapore: 1. Sturnidae (mynas and starlings). Unpublished report to the Ministry of National Development, Singapore, 97pp.

, and present-day common mynas are now mainly restricted to rural and beach habitats. It therefore appears that increasing urbanization and availability of human waste as a food source has favoured the Javan mynas’ shift towards a more human-tolerant population.

Footnote Macro

Feare, C. & A. Craig, 1999. Starlings and Mynas. Princeton University Press, New Jersey. 143-145 pp.




Taxonomy & Systematics

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)

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).

Footnote Macro

Cabanis, J. L., 1851. Museum Heineanum: Verzeichniss der ornithologischen Sammlung des Oberamtmann Ferdinand Heine. R. Frantz. p205. URL:https://play.google.com/store/books/details?id=M_sYAAAAYAAJ. Accessed on 2 November 2014.

 The original description is in German and written in the final footnote of the page. It roughly translates as the following: ‘The Javanese bird differs from the following species by a completely yellow beak and by, with the sole exception of the white undertail coverts, a monochrome gray underside.’

Two syntype specimens were collected and designated from Java, Indonesia and are currently deposited at the Museum Heineanum Halberstadt, Halberstadt, Germany.

Footnote Macro

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.

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.

Footnote Macro

Feare, C. & A. Craig, 1999. Starlings and Mynas. Princeton University Press, New Jersey. 143-145 pp.

 For example, various authors have referred to A. grandisA. 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 

Footnote Macro

Amadon, D., 1956. Remarks on the starlings, family Sturnidae. Amer. Mus. Novit. 1247: 1-16

, while Sibley and Monroe (1990) awarded the Javan myna full species status on the basis of markedly different features from the jungle myna, especially regarding bill colouration. 

Footnote Macro

Sibley, C.G. & B.L. Monroe Jr., 1990. Distribution and taxonomy of the birds of the world. Yale University Press, New Haven and London

 However, Inskipp et al. (1996) considered the Javan myna, pale-bellied myna, and great myna (A. grandis) to be more similar morphologically to each other than to the jungle myna, and considered them conspecific.

Footnote Macro

Inskipp, T., N. Lindsey & W. Duckworth, 1996. An annotated checklist of the birds of the Oriental region. Oriental Bird Club, Sandy.

 Feare and Craig (1999) awarded full specific status to the Javan myna in agreement with Sibley and Monroe (1990), and additionally considered the pale-bellied myna as a full species as well.

Most recently, Wells (2009) considered the allopatric pale-bellied myna to be a distinct species from the Javan myna, but predicted that natural experiments created by the northbound invasion front of Javan mynas encroaching into jungle myna territory in peninsular Malaysia would eventually show jungle mynas and Javan mynas constitute one biological species.

Footnote Macro

Wells, D. R., 2009. The birds of the Thai-Malay peninsula (Vol. 2). A&C Black. ISBN 978-0-7136-6534-5.

 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 Acridotheresspecies 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.).

Footnote Macro

Zuccon, D., E. Pasquet & Per G.P. Ericson, 2008. Phylogenetic relationships among Palearctic–Oriental starlings and mynas (genera Sturnus and Acridotheres: Sturnidae). Zoologica Scripta37(5): 469–481.

However, the exact relationships between these three taxa remain unresolved.


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)

Footnote Macro

Zuccon, D., E. Pasquet & Per G.P. Ericson, 2008. Phylogenetic relationships among Palearctic–Oriental starlings and mynas (genera Sturnus and Acridotheres: Sturnidae). Zoologica Scripta37(5): 469–481.


References

Display Footnotes Macro


This page was authored by Gabriel Low
Last curated on 2014