Very loud 4am bird - Berkshire

Hi all,

Every morning at 4am recently a bird cries out very close to my window. It sounds like none of the birds mentioned, in fact no bird I’ve ever heard before.

It gives out three short, very loud cries with a half-second gap between them, goes quiet for 20 seconds or so and then does it again. The sound is bizarre, almost like the noise that the giant bird makes in the Pixar film UP.

It has to be a fairly large bird given the volume, not like a tit or blackbird, and it can fly quite fast given last night it was practically on my roof and then about 30 seconds later it’s same cry I could only just hear in the distance.

Hope you can help it’s driving me mad.