It seems you cannot help but learn things when you observe them long enough.
This is a very short story of an adult Kelp Gull (AKA the Southern Black-backed Gull). It is quite a robust, strong gull (image #1) but can be also quite an elegant bird (image #2).
Mongo was sitting in front of a small sandstone shoal situated at water level. One of these large gulls was coming from the distance with something in its beak. All the while it was gaining altitude and started to circle the sandstone shoal. As it got closer, it became clearer that the thing in its beak was a local sea creature that looks like a large garden snail (image #3).
At a strategic point in its circling flight, the gull deliberately released the snail which then fell with great precision onto the sandstone below (images #4 and #5).
As the snail fell to the rocks below as intended, the gull began to follow it down (image #6).
The gull followed it down and inspect it. It seemed disappointed and It picked up the snail and again flew high over the sandstone shoal. It again dropped the snail from quite a height. Again, it landed on the sandstone. This time when the gull flew down to it, found it broken open and began to eat its freshly open reward (image #7)
Some time later, either the same gull or another of this species did exactly the same thing with another snail. This was starting to feel like when you first see such a scene in an Attenborough documentary. Mongo was aware that some birds use height/gravity to break open their otherwise hard to get at food. Mongo believed this behaviour was limited to a few far more intelligent bird species. However, now having seem it several time, there can be no doubt that this gull is one of those species.
D800E with nikon 200-500mm and monopod.