Debugging mobile menu malfunction

Hello:

I am very new to WP, and am struggling with solving this problem. The website is located here:

http://adirondacklivesteamers.org/

The problem I have is with the mobile menu not working, which also shows up if you narrow your browser enough that the menu cannot show. I have looked through my html page source to try and locate duplicate .js entries, and disabled the ones I found with the WP download manager. But it still does not work, and I’m at a loss with how to fix it.

Any suggestions are greatly appreciated.

Thanks in advance