I agree with Steve on his main point, there is no excuse for disturbing the birds to the point they abandon their choosen nest site.
It does raise a question with me, how many "birdwatchers" are photographers and vice versa, big grey patch there I think.
Last year I had to stay with my parents down south, I wanted to photograph dippers there so got info on lathkill dale in derbyshire, I was horrified to find out that a photographer, had been in the stream moving rocks around to provide a better photo opportunity, this resulted in the pair abandoning their chicks. :C
I refused to go there after that and found my own spot, in a different part of the county well away from the hordes. The pair I found had a nest under a bridge, I went there once a week watching from the car, then very early in the morning while the adults were away, I set up a camouflaged position near the bridge.
Took some great photos of the adults hunting, until a fly fisherman popped along, he didn't see me for quite a while and was a little startled, but for the hour and a half he was there the adults could not feed their young, standing off just up stream with a beak full of grubs, the young got impatient and started to call, the adults replied. The fisherman left and as he did one of the chicks fell or jumped out of the nest, followed by 2 more. :flyaway:
Now I was stuck there like it or not, I couldn't move incase the adults left, slowly but surely the chicks began to adjust to their new surroundings, it only took about 15 mins before they too started to bob up and down like the adults, within an hour they were hunting in the shallows, the call from the adults drew them up stream and I was able to pack up and watch them move further up stream from the car. :stuck:
I'm not sure whether or not they would have left the nest if the fisherman had not been there, but I had watched the adults from first light feeding about every 10 mins or so, and for the 1 1/2 hours the fisherman was there they couldn't feed.
The pictures "wow they stretch" "woohoo, so this is where the food is" "this stuffs cold, how do I get back up"