Firefox permissions issues
Sometimes, Firefox requires you to explicitly grant permissions to run the extension. If you don't see the "Add-ons" button, this may be your problem.
If you look in your toolbar, you should see a "puzzle-piece" icon like this one. Does it have a green dot beneath it when you are on a Trip Report? If it does, you need to perform the following steps. If there is no green dot, you can stop reading; none of this pertains to you.
Click on the puzzle-piece icon to open the "Extensions" menu, and click on the gear icon that is at the right of "eBird trip report utilities". Important! Be sure you click on the gear icon, don't click on the text to the left of the gear icon.
In the next menu, click on "Always Allow on ebird.org".
After this you should be all set.