Squeaky Toy Nocturnal Bird Call and Reply

Hi all, Last night as I went to bed around midnight, there was a really load squeaky toy sounding bird sound, which was then immediately replied to by another a little further away. It was a short two tone squeak, which was incredibly loud. I think for a while there were three joining in. I've never heard this before. Can anyone suggest what it might be? I have an MP3 of the calling, but I don't think I can attach it to this forum.

Thanks