The swallows lost their nest again and an egg too

When I went through the tunnel under 9800 South yesterday, the swallow nest was intact, but when I went through the tunnel today, the nest was on the ground and an egg was smashed on the ground. It's too bad, but I assume the city has to insure the safety of persons using the path. A lot of people are paranoid about animals, and someone in the city government apparently felt the birds shouldn't be nesting in the tunnel. I walk through the tunnel about 20 times per week, been doing that for a lot of weeks, and I've never been attacked by the birds. The nest was up about 10 feet, and one would need either a long stick or a ladder to knock the nest down. For this reason, I assume it was done by a city employee not just a walker going by.