[Jas]

I have 3 (female ) khaki Campbell's 16 weeks old and one of them is really loud as though quacking for attention all the time. It only needs to get a glimpse of us through a window and thats it!
I think maybe our own doing as one of us will go out and try and quieten it down as we don't want the neighbours complaining. It does quiet down when we go out
It was the dominant duckling and bolder than the others two from day one
I have read it can be a hunger thing but plenty of food and garden to find food or adolescence and may grow out of it.
Any tips? Best to 'try' and ignore it till it realises no one is coming?(easier said than done, we do try)

[Marches Farmer]

Maybe it still considers you its Mama?  Is there anything scary in its line of vision it wants reassurance about (could be washing flapping on the line, vehicle noise, a passing cat ....)?   Do you feed it when you respond?  If so you're rewarding it for quacking. 

[Jas]

I think it associates us with food. I must admit they do get fed treats when we go out but not often. It's been over an hour now since I got In and as soon as they heard me the one has been quacking loudly constantly.Have ignored so far but bet the neighbours aren't happy
Hopefully perseverance and it will get the idea

[Clarebelle]

I think ducks are highly intuitive. Mine quack loudly in the morning, same time everyday, right outside the window. They want breakfast and won't shut up til they get it! I would agree that it probably knows it will get food or attention if it makes a racket.

[Black Sheep]

Ours have got used to a routine and know the sound of the back door opening, which in the morning heralds the food being taken out, and quack loudly when they hear it.