The Grey Wagtail (Motacilla cinerea) is a widely distributed wagtail species that spends the summer months in the Paleartic region. In winter, they migrate to Asia and Africa. One of the destination in Asia is Singapore, where the species is listed as an uncommon winter visitor.
It is one of the earliest migrant, with reports of the birds appearance as early as mid-July. In the field, they are quite likely to be confused with the commoner Eastern Yellow Wagtails. Yet, they differ from that species both morphologically as well as behaviourally. Unlike the Yellow Wagtails, the Grey Wagtails have grey upperparts. The underparts is white in non breeding plumage but turns yellow in breeding plumage. The male has a diagnostic black throat and breast. The vent is yellow throughout. Behaviourally, this wagtail prefers to hang around streams and drains, with fast moving shallow water, in contrast to the Yellow Wagtails that are more land based.
So in order to see them, one has to check streams, ponds, drains and canals. Since they tend to come back to the same place year after year, they can be quite easy to track down if one knows about previous season sightings. There is one canal at Bukit Batok West that almost always have 1-2 Grey Wagtails at the right time of the year. Other recent sightings include the small pond in Jurong Lake Garden and the canal just outside of Buona Vista MRT station.