Spring cleaning, continued

In between some of the sidewalk cobbles, I found sand piles that were mountains compared to the ant-hills.  There were no ants around these sand piles, nor could I see anything inside when I peered directly down the large, round entrances.  However, as I explored a nearby forested park, I came to the top of a (real) hill that was littered with similar sand piles.

One of the many nests on the hill.

Here, the holes were not all empty.  As I walked along the path, I noticed a quick movement as something disappeared down one of the tunnels.  I crouched nearby and waited -- and after a moment a fuzzy head re-emerged.

A fuzzy head peeks out of the nest.

The occupant of the nest was a mining bee.  Unlike some other bee species (such as honey bees and bumble bees), mining bees are not social.  Each female has her own nest that she provisions with food for her offspring.  Nevertheless, these bees often nest in close proximity to each other.

Two of the mining bees crawling out of their holes.

The two bees pictured above seemed to live too close for their comfort.  Repeatedly, they would crawl forward to inspect each other, then rapidly retreat back into their nests before returning to the surface for another round.