The garden has been home to black ants, Lasius niger, since the day we moved in. We have them at the front of the house where they nest in sandy soil adjacent to the drive and in the back garden under the house and patio. Sometimes in the spring they come in, finding the cracks between the patio door woodwork and the wall, and sometimes in summer the newly emerged winged males and females climb up the wall and fly off, always towards the south, on their nuptial flight. It is a wonderful, if brief spectacle and it often seems to occur on humid days in July and August. It is over in about twenty minutes.
My mother used to pour boiling water on the nests and I used to too, but these days I have a more laisser faire approach to ants after I noticed green woodpeckers feeding on them greedily last summer. Generally, when there is this much protein about, something will notice and appear for a meal.
Yesterday we watched another batch of queen ants appear beside the patio doors, gathering ready to set off on their flight and within a few minutes blackbirds, sparrows and starlings had appeared to enjoy an antfest. The sparrows jumped up to take them as the ants climbed onto plants, the blackbird caught them and when she had several, fed them to her youngster. The starlings were divided in their approach. Some picked up and ate the ants, dancing around, I assume to avoid being bitten by the wingless workers, but other starlings were grabbing the ants and then putting them under their wings.
It is thought that the ants squirt formic acid as a defence, but starlings make use of the acid as a pesticide to rid themselves of parasites of various kinds. One bird collected a beakful of queen ants and preened its feathers through the ants before placing them under its wings.
This morning there was almost no sign of the abundance of yesterday. Just this single ant on a discarded wing.