We only saw Japanese Wagtails (Motacilla grandis) twice and in rivers with gravel stones. We were fortunate to observe (from some distance) an adult pair feeding a single juvenile. Both parents were feeding the young.
Post 1 above shows the habitat with a juvenile and adult in the image.
Post 2 above shows an adult with prey for the juvenile.
Post 3 above shows an adult with prey caught for the nearby juvenile from the river (not rocks or banks). The one prey I saw able to determine was an aquatic Plecoptera (Stoneflies) nymph.
Post 4 above is of the juvenile.
Amar-Singh HSS (Dato’ Dr) – Ipoh, Perak, Malaysia
Location: East Hokkaido, Japan
Date: 9th June 2019
Equipment: Nikon D500 SLR with Tamron SP 150-600mm f/5-6.3 Di VC USD, handheld with Rode VideoMic Pro Plus Shotgun Microphone