Rare birds

On a visit to Taichung today my attention was drawn to these birds being photographed by a passerby. Believe it or not these are 3 chicks not yet able to fly. Our photographer friend explained that she had been following them since they first hatched as chicks and that they were now ready to take to the skies. The chicks must have been about the size of chickens so the adults, who were nowhere to be seen, must have been the size of a heron or stork. The rather small nest can just be seen below them. It is certainly a bird I am unfamiliar with so anyone with an idea of what they might be let me know.

Update

After almost a year in Taiwan I conclude that these must be Night Heron chicks.