I remember, years ago, the excitement of seeing a heron catching a fish in the canal at Skipton and climbing the bank with its prey in its beak. So we should think ourselves fortunate to be able to see the heron in action, if only they stuck to their fish diet. Here it is tackling an eel.
But on either side of the pond are streams which are death traps for ducklings. 
The heron moves quickly for a meal and the mother is usually unable to deter them. 
But most of the time they are patient and will stand in the lily pad motionless waiting for fish or an over-confident duckling.
As hunters they are planners and tacticians and you can see them try different areas to fish if they are unsuccessful.
They stalk the young ducklings and I’ve noticed recently with the thick cover of the reeds that they wade inside even if they lose their ability to escape quickly. 
They are a protected species and all we can do is clap our hands to frighten them off. However by mid-August when the ducklings are a decent size the heron reverts to fishing and is tolerated until the spring.
A second one has arrived – but there were no casualties. I think the nearest one just wanted a nap
pondlifeweb 