I heard a strange four-note call, quite loud and coming from an overgrown field with water pools next to my house. The location is N Scotland on the E coast, and it was about 10:30 a.m. The Merlin Bird Sounds ID app didn't know what it was. Any ideas? Is it wildlife or just some livestock or machine? The video is here https://youtu.be/a0wxayYp-ek
Sorry I can't help with ID but this will bump your post up so that others can see it ... we really need a chap called TJ as he's very good at bird calls!!
2013 photos & vids here
eff37 on Flickr