Northumberland 23
Northumberland

Highly disguised?

Getting up early in the morning when the suns angle catches them, frosty mornings are the best for this; the other option is of course from the air............

That's the stuff. How to recognise a soil mound when in the field.
Shadows, yeah. More likely to be sunset than sunrise for me though, I'm a lazy beggar.

Aerial? Oh how I wish...