Javan Myna, a successful invasive species in urban Singapore!!

In modern Singapore where urbanization has increased the proliferation of buildings and residential area, one of the most successfully adapted bird species is the Javan Myna (Acridotheres javanicus). It is not a native species but was brought into Singapore around 1920s as pet bird (Gibson-Hill, 1949). These birds that we commonly see around open air hawker centres have wide range of nesting and feeding tolerance.

Javan Myna is hollow-nesting species which nest and breeds in protected hollow found either naturally in trees or artificially in buildings. The aggression and monopolisation of nest hole of Javan Myna reduce breeding success of native birds (Yap et al., 2002). Hypothesized by Huong and Sodhi (1997), mynas are one of the factors leading to the decline of native hole-nesting oriental Magpie Robin (Copsychus saularis). In addition, mynas are capable to nest in artificial hollow found in man-made environment such as roof space. The loose nesting requirement has increased the survival rate of Javan Myna in urban areas.

A myna nest under the rooftop tiles

Figure 1: “A myna nest under the rooftop tiles” by Lim Jun Ying. Bird Ecology Study Group, Nature Society (Singapore), 3 January, 2007. URL: http://besgroup.blogspot.com/2007/01/javan-myna.html (accessed on 12 April, 2010)

Besides feeding on insects and fruits, the Javan Mynas can feed on human food. These birds are frequent dwellers of rubbish dumps and often found walking around open air hawker centre or canteen searching for leftover food. The population of Javan Myna grows and spread quickly in urban city especially in residential zone which has abundant supply of human food residue (Yap et. al, 2002).

A myna feeding on human food residue

Figure 2: “A myna feeding on human food residue” taken by myself on 14 April, 2010 at The Deck, NUS.

Even though Javan Myna is a successful species in urban city, the increasing population size posts threat to native bird species in terms of competition. Large population of myna would also cause damage to agricultural crops and spread agricultural weeds (Lim et al., 2003). If this condition is not well managed, the Javan Myna might become a pest to human community.

References:

1. Gibson-Hill, C. A. (1949). An annotated checklist of birds of Malaya. The Bulletin of Raffles Museum, Vol. 20: 5-299.

2. Huong, S. L. & Sodhi, N. S. (1997). The status of the oriental magpie robin, Copsychus saularis, in Singapore. Malayan Nature Journal, Vol. 50: 347-354.

3. Lim, H. C., Sodhi, N. S., Brook, B. W. & Soh, C. K. (2003). Undesirable aliens: factors determining the distribution of three invasive bird species in Singapore. Journal of Tropical Ecology, Vol. 19(6): 685-695.

4. Yap, A. M. C., Sodhi, N. S. & Brook, B. W. (2002). Roost characteristics of invasive mynas in Singapore. The Journal of Wildlife Management, Vol.66(4): 1118-1127.

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