I've been there recently - a nice place for a walk, fresh air and photo-taking. A leisurely walk with rests will take about 3 to 4 hrs (if you want to complete the whole loop). Would be nicer to visit during the bird migratory period.
Things to note:
- Bring finger snacks, water & insect repellant
- If going by public transport, the bus (SMRT 925? from Kranji MRT stt) arrives at intervals of every half hour on public holidays. The bus arrival timing are listed at the bus-stop.
- Try to avoid groups of noisy ppl if you wanna catch interesting creatures
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