Beaver Sabotage?

This is one of the pipes like many in our communities that carries runoff from the storm drains and sewers directly into the lakes and streams. A few weeks ago I found this peculiar pile of twigs at the base of this pipe. Although the pile hasn't gotten any bigger since the seasonal flow stopped, it looks like beaver sabotage. Can't blame him for giving up so easy, it's not a healthy environment in which to live.