I have lots of this type of droppings on the garden. Does anyone know what animal's droppings are these and how to prevent? The animal likes to poo on weeds as well.
They're worm casts by the look of them.
Worm casts so basically just soil,they brush away easily if dry!
So it is normal that they are all over the garden.
It might mean the ground is a bit waterlogged and the worms have been pushing their casts out in order to breathe. It would be worth spiking your lawn all over with a fork and then brushing sharp sand in to the holes to create better drainage.
It's a sign that the soil under your lawn is in good heart and is being aerated by the worms and they are dragging leaves down below the surface to add nutrition and improve the structure of the soil.
But as has been said, on a dry day deal with them with a stiff broom before mowing otherwise you'll get little muddy patches