Sungei Buloh Wetland Reserve (SBWR) is a slightly ulu nature reserve in the far, far away northwest.

It is an ecological jewel of this highly urbanised Singapore where you can see usual wildlife such as the otters and herons, as well as not-so-common wild crocodiles nesting and chilling around here.

What might not be very well-known to non-nature fanatics is SBWR's international importance to appreciable numbers of migratory birds, as the area is part of the East Asian Australasian Shorebird Site Network.

However, in recent years there have been growing numbers of house crows in the nature reserve which can be problematic to both residential or visiting birds as reported by The Straits Times.

One birdwatcher, Lim Kim Chuah, has observed flocks of up to 50 crows in SBWR.

It remains unclear why the crows are gathering at SBWR, but wildlife consultant, Subaraj Rajathurai,suggested that that the crows might be driven from their habitats in Johor, located just across SBWR and/ or attracted to a food source near or within the reserve.

However, the crows brew trouble for other nesting birds in SBWR as visitors have observed house crows mobbing other birds.

One possible reason, according to nature guide Ivan Kwan, is that the crows might be "water testing" to target the weaker birds as preys by disturbing them first.

Other nature enthusiasts have also seen crows raiding little heron nests in the nature reserve. This might discourage some bird species to nest in the area due to the presence of these crows which consequently means high risk of nest failure.

The group director for conservation at the National Parks Board (NParks), Wong Tuan Wah, also cautioned that non-native house crows' mobbing habits can be detrimental to other birds, should their population increase.

NParks will seek out and remove any house crow roosts and nests within the reserve to control the crow population.

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Top photo from screenshot of YouTuber Solomon's video

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