Are you afraid of snakes?
You really do not need to be, they are just here to help keep a balance.
I am posting this late, it happened in June, but it has a scary quality fitting for the week of Halloween. Scary that is if you are a wren.
Suzy and I were aware of a pair of Carolina wrens tending a second or third brood in a nest box off the second floor deck on the side of the house 15 FEET off the ground. Yes, 15 feet up.
All seemed to be going well until one day, when the pair became highly agitated, fussing, alarm call after alarm call. AND, and this is a big AND, neither were going near their brood, their raison d'être.
Leaning out with a long stick, I opened the box, and viola, soon discovered the the cause of alarm. A smallish black rat snake had climbed the 15 feet and entered the box.
Using the stick to slowly clear out the nesting material I found no eggs, no nestlings, only the snake.
Such things happen. That's why birds often have a second or third brood.
But, if you feel uneasy in your cozy nest. You better peek under your mossy bed.