Anita,

I have a similar situation in that my bluebirds are back for a second brood. The house wrens didn't bother the box during nest building (and the box had been empty for about a month and there were no sticks).

Mama laid her 1st egg this morning and this evening, a house wren took out that egg and smashed it at the base of the box.

I think that now I'd say "the rule is that there are NO RULES!" I've had house wrens attack several eggs or several chicks, never just one egg.

As far as putting up a wren guard, the problem you have is that the house wren has been in the box. And where there is one house wren, there are usually more near by.

The reasoning behind the general rule of putting the wren guard on the box when the 1st egg is laid is that the female is less likely to abandon the nest if she can't figure out the wren guard. It's also hard to say whether your female is 'with egg' and I'd hate to see her not be able to get into the box to lay her 1st egg, if that makes any sense.

You could wait till it's afternoon and the bluebird hasn't laid an egg and put it on. If she can't figure it out, I'd take it off till the afternoon of the next day, etc.

Good luck, Linda in NW GA...

I would go ahead and put it up if you think she has used the box with the guard before. I like Lindas Idea though, put it up in the afternoon to be sure she can get in. If you havent see her go in take it down in the evening and try again tomorrow. I sure hope it works, I have heard that turning the box 1/4 turn can also outsmart a Wren.

I put the guard back on this morning, and I have seen the mother bird in the nest during the day. I hope this is a good sign. will keep an eye on the situation. i decided that I would rather take a chance that she would abandon the box than have her lay eggs and lose them to a wrens.

You can always move the box now, guard and all! Dang Wrens anyway.

with the camera on I can see the mother BB busily building her nest with the wren guard in place. that is good. Now I just hope the wren that put the sticks in the box are busy with babies in another neighborhood!

It's Monday morning and there is one egg. i wonder if this is the same bird that laid all her eggs in the afternoon for the first nesting. It's always interesting.

A

Well the egg is gone this morning, and the wren guard looks a little spattered with something yellow, could be yolk? I didn't find the shell or any bits of shell around but I'm assuming it's the wren that still knows where the hole is, despite the wren guard. I've opened the door and mama bluebird will have to start over somewhere else. At least I've caught it before a whole nest of babies perished. That's it for me for the second year only one nesting, when I've had 2 and 3 in the past. I hate those wrens.

So sorry Anita. Did the guard have sides? I wouldn't use a guard without sides. Some wrens are so determined. I see them crawling all over a box and it makes me nervous. I have 2 boxes in my yard on telephone poles (from when I didn't know better) that I block off with a piece of cardboard and duct tape just like the guards I make. I leave the cardboard off for a week or two when they arrive and then close them up. I always hope it will tell them when you see the cardboard don't even try to get in. So far I've been lucky.
Cathy

Hey Cathy, yes it has sides but the wren had already put sticks in a while ago. I was hoping that the wren had gone elsewhere by now. No such luck