2013 Nissan Rogue Engine air filter housing

You can often get road debris being draw into the bottom of the air box, the filter excludes this from entering the engine, just clean it out and don't worry about it, you often see all manner of strange things being caught up in the lower air box, I have seen small birds, mice and rags that have been drawn in.

Thank You for your response. We think the stuff was dog food and the squirrels have been using the air filter for a larder.

Its a warm and dry spot, until you start the car and they get a real nasty surprise, we see a lot of this around winter time.