This past year, when I cleaned out the boxes, I noticed that the second box was filled with a stick nest from the wrens. One year it was a dummy nest. The next year it was used (the spiders webs are the tell-tale sign). What I didn't realize was that wrens destroy nests and crack eggs.
This year I was thrilled that the newer box was inhabited by bluebirds. But, they were soon kicked out by black capped chicadees. I was thrilled. I watched them every day as they went back and forth. I figured eggs must have been laid, and soon we'd have hatchlings. Then I noticed 2 days ago that a wren flew in and out of the box. OH NO. And, unfortunately, this is what I found.
Broken shells! I opened up the box, and it was empty, save for a stick. Those bad birds cleaned out the chicadee nest! Grrrr. I checked again today, and the box is filled with sticks and some spiders webs. The momma stood by and sung at me, telling me to get lost. I guess I'll leave her to raise a family there. She does have a sweet song, after all.
On a brighter note, about 10 feet from the nest box, some mockingbirds are building a nest. It is really close to the edge of the forsythia bush, so it should give me some good glimpses into the nest. And they also like to perch on the nest box- maybe they'll chase the pesky wrens away.
**I just went out and looked, and the bird (I don't know if the male or female builds it) has started to line it with soft materials- bits of cat hair, twine, grasses, and even a little bit of moss.