A large, wading migratory bird known as the Whimbrel was recently spotted again at Sungei Buloh Wetland Reserve last month, 19 years after it was first attached with a ring in 1995.

This is the longest record for the repeat sighting of an individual Whimbrel species here, said the National Parks Board in a statement on Sunday.

In bird ringing, a small ring with a unique serial number is attached around a bird's legs for easy identification. Measurements of the bird, such as its weight and length, are recorded for research purposes.

Mr Wong Tuan Wah, Director of Conservation at National Parks Board, said: "Repeat sightings of the same individual can be quite rare and we are very fortunate to be able do so. "

The Whimbrel and other migratory bird species can still be seen at Sungei Buloh and visitors can see them until around late March, which is usually the end of the migratory bird season, he added.

Bird ringing helps researchers to determine the migration patterns and longevity of different bird species.

Another significant record for the repeat sighting of a bird was in 2011, when a Common Redshank was sighted 21 years after it was ringed.