Sand Digger Wasp Labour
Sand digger wasp (Ammophila sabulosa?) removing nest spoil. Thursley Common, Surrey, UK.
Remarkable creatures and a joy to watch. Once the nest is dug they stockpile it with caterpillars but this one soon plugged the unfinished hole and took a rest from its labours nearby.
See this excellent introduction to heathland solitary wasps for more.