I went back to the lakeshore tonight to look for the orchids that I found this past fall when they had gone to seed. Sure enough, there are a few patches of wild orchids just coming into bloom now. We were there close to sunset tonight and the ants were feeding and getting trapped inside the flowers. I am not sure yet what species of orchid this is, but it is likely Epipactis helliborine. If you look closely enough at the first picture, you can see an ant inside the flower. The third picture shows four plants with many unopened flowers.
For comparison purposes, here is an Epipactis helliborine I found in Victoria three summers ago, also growing in the city.