Add on battery disconnect knob missing

[KA9J]

A year ago I put one of those inexpensive battery disconnects on my negative battery terminal to isolate my battery 100% when it's not being used. Now I have no drain on my battery and it stays charged for months. I charged the battery about 3 months ago so it was time to charge it again. When I opened the front storage compartment (where the battery is located),there are 2 vents about 4" square that a bird had flown through carrying straw for a next. I wasn't too surprised at this because earlier in the winter we also had a bird trying to build a next in the back of our 5th wheel hitch. We kept on chasing it away and stuffed old towels in the openings to prevent the bird from entering the 5th wheel hitch. Anyway, I went to tighten the green knob on the battery disconnect and it was missing. I searched all around the battery and it wasn't there. I suppose the bird might carry it away if he felt it might be hazardous to the nest, but how did she get it unscrewed completely out of the body of the disconnect?




In the pictures below, the one of the battery compartment is rotated 90 degrees CCW, and I couldn't get the ROTATE function to work when I posted it. Just turn it 90 degrees clockwise in your head.