Something to seal cubby holes in bed

Is there something made that you can use to seal up the cubby holes when not in use? I drive a service truck all week and my truck just sits under my carport and birds have decided that the cubby holes are perfect for building a nest.

 

Better than the exhaust pipe...

 

You can pull them off and put flat panel over them. Use 3m double side adhesive or hook and loop tape.

 

Guess thge simple answer is a piece of plastic or aluminum cut to size and Velcro. I've been considering doing something similar but with a 1/4 turn hatch or two to hold it in place. Ive built enough boat hatches and cubbys that the entire project shouldn't take more than an hour or so.

 

Put a cat in each one.

 

Lol!

 

Then I would need a dog for each cat.

 

Saw someone else on here mount some magnetic strips on the either side and the bottom of the cubby, and then used a thin piece of steel cut to size and painted black.