Probably a frog - underwater rachet in disused sewage works. This water was a slightly disturbing yellow/ochre colour and it was impossible to see what was making the sound. There were plenty of frogs nearby so maybe it was one of those or less likely an insect.
Peter Cusack
2016-04-07
nafarroa, ura, intsektuak - xomorroak, animaliak, hidrofonia, metala