Many swallows at the 106th South Tunnel

A flock of swallows have chosen the tunnel under 106th South as their new neighborhood. If you look closely at the openings in the nests, you can see the beaks of swallows that are in the nests. My guess is they are cliff swallows because they don't have forked tails, have the correct coloring, and their nests look like those from cliff swallows. Click a picture for a larger view.