A Lonely Egg and a Conundrum

The Lonely Egg, first shot

Recently I've seen a Carolina wren bringing bits of grass and twigs to my bathroom window sill, but there's no real nest, just a small pile of brush. They often build false nests to distract predators, and I thought this might be one. 

Then yesterday I looked out and saw this single egg. I looked it up and it appears to be the egg of a house wren, not a Carolina wren. I thought with the unfinished look of the nest and the lonely egg, it wasn't viable.  But Sialis.org says house wrens lay one egg a day and the female doesn't begin incubation until the penultimate egg is laid. So it could be the first egg and perhaps a young bird whose nest-building skills aren't fully developed.

House wren, courtesy of Sialis.org

This morning I went back to take a picture and met the bird again. She flew off immediately and I took a hasty picture (that's why it's blurred), hoping not to disturb her too much. The thing is, I'm sure the bird is a Carolina wren, but the nest and the egg are quite different. And the two wrens look different.  Mike took the Carolina wren picture at the feeder. We see lots of reddish-brown Carolina wrens with the distinctive white streak above the eye.

This is the bird we see,
taken next to the feeder.  Definitely
a Carolina wren.

So what do we have? I really don't know, but I'll keep watching and see if there's another egg. If you know  about wrens or their nests or eggs or if you've seen anything similar, please let me know.

 I just went back to see if I could get another picture. Had to use a flash because the egg has been moved into the corner.

Lonely egg moved to corner--second shot

This is the second "nest." the one in the living room window. One egg early this morning , but about 10 o'clock we checked and found a second egg. I hope they hatch. We should have a good view of the birds if they do.