Interspecific interaction of birds at Pasir Ris
The place: near the Pasir Ris MRT Station, Singapore. The time: around 8 am. The date: 22nd December 2005. I noticed this whole assemblage of different species of birds on the grass, some foraging, others just looking around. There were crows, mynas, egrets and rock pigeons. More were continually joining in, especially pigeons and crows. The egrets didn't really seem to mind and almost seemed oblivious to the 30-40-strong gathering before them.
Could the spot be a designated meeting ground for birds? After all, birds sometimes do communicate and discuss eating places, like Singaporeans. Or could the spot, judging from the seemingly limited interspecies interactions, be just a good spot for forage or rest? If the latter, it is amazing that there is no or little competition or observable territorial behaviour among different bird species!
Text and image by Lim Junying.
Comment by our bird specialist, R. Subaraj: I am glad that you were observant enough to notice this. Most people, including many birdwatchers, would have simply ignored the gathering as it mainly involved common urban species.
Based on the photo and what you have written, I would think that the area is a good feeding site. The Cattle Egrets (Bubulcus ibis) normally hunt insects in fields and the mynas and crows are opportunists who would also catch and eat insects. The patch of grass may be rich in invertebrate life due to some unknown reasons (dampness, freshly cut grass, etc.). As for the pigeons, they may focus on seeds but could be eating invertebrates as well, being highly adaptable.
As for competition, if there is plenty about there should be no problem. However, it may be interesting to study if they are working as a team, in a birdwave of sorts. A birdwave is a gathering of insectivorous bird species that move together to stir up more insects. This is a common occurrence in forests, from the lowlands to the mountains. The more birds involved, the more insects are stirred up and the better chance of finding a buffet, such as a tree of caterpillars.
Does this behaviour occur on the ground and in more open country or urban settings? Should be fun finding out.
Keep at it and nature never fails to amaze!