Help identifying a bird

Hi all

I am looking for help to identify a bird - I can hear it all day every day, it’s very loud but I cannot see it to figure out what it is and am so curious. Perhaps someone will recognise the sound it makes - including an audio clip here which I hope helps. At first I thought it was an alarm or just a beeping noise but have come to realise that it is in fact a bird - not the usual chirpy sounds I am used to hearing so am puzzled! 

Bird.m4a

Thanks in advance!