Ants in my pants

Unlike the ant-hills between the cracks in the sidewalk, the ant-hills that I came across in a nearby park presented real obstacles -- due to their size, the number of ants defending them, and the logs that had been placed around them. 

A wood ant (Formica sp.) nest.

Disregarding the implicit warning of the log barrier, I came closer for a better look at the ants.  The ants were swarming in and out of crevices in the stump where the colony had made its nest. 

A close-up of the wood ants.

Although not quite as apparent in the top picture, the ants had also spread out over the logs and throughout the surrounding area (including where I was standing).  Some of the ants, such as the one pictured below, were returning with captured prey.

A wood ant carries its prey back to the nest.

Meanwhile, a few others were crawling over my shoes, and at least one made it into the leg of my pants before I decided it was time to continue my walk.