Intermediate Egret or white morph of Western Reef Heron ?

Heard at the swimming pool of Beach Rotana Ina palm tree. It’s got dark for me to be able to spot the bird. this is a iPhone sound recording if it does not play please email back and I will change to right format

Hi all, I have accumulated some observations I could not ID with any certainty and would appreciate any help i can get with them. many thanks in advance! bird 1: 24-august, Expo lake. I suspect a clamorous reed warbler but it looks too slender & too much contrast between upperparts and underparts ... bird 2: 25 dec, al qudra lake. I think it's a leaf warbler but can't decide which one. either bird 2 again or bird 3, i'm not sure. this is 6 minutes later in the spot I saw bird 2

I would welcome any advice on the identification of this warbler, seen when the fog cleared at Al Rafa'a (just along the coast from Dreamland in Umm Al Quwain) on Saturday morning. Visually it was a small, distinctly grey bird with whitish underparts, long-tailed, short-winged and quite flighty; settling only for seconds and then off to the next bush. I didn't see any obvious pattern of tail movements and it was silent as it moved around. I had heard 'tchk' calls close-by earlier but assumed this was a Lesser Whitethroat seen earlier, and couldn't certainly attribute tha call to this bird.