Let's follow a Heron.

I stood in the shade of a field, when this guy appeared, and I decided to follow him.

So, join me into the sunlight to see where the bird was going.

It is a Grey Heron, and they are normally seen at water bodies, such as dams, wetlands, rivers, and lagoons. But not this one, as there is no water at this field. I have to say that there is a river about 300 meters from the field, and maybe, the bird decided to search for some rodents, or small snakes. I posted a heron with a snake, a long time ago.
Let's see what Wikipedia has to say about the grey heron.

Grey herons are apex predators in their aquatic ecosystem.[16] Fish, amphibians, crustaceans, and insects are caught in shallow water with the heron's long bill. It has also been observed catching and killing juvenile birds such as ducklings, and occasionally takes birds up to the size of a water rail or white-throated rail. Small mammals such as water voles, rats, stoats and young rabbits are additionally caught. Recently, the grey heron has been observed to use the 'stress and wash' technique which is believed to make great crested newts (Triturus cristatus) and smooth newts (Lissotriton vulgaris) more palatable by flushing their skin free of toxins before consumption.