BB Nest Attacked - Wrens?

[Jeff Nelson]

I was hoping that this summer would be a great summer for our bluebirds. Last summer was devastating as I battled 'smart' coons that plundered just about every nesting box we have along our BB trail.

We have about 25 BB houses distributed around our 40 acres and for many years attaching and setting rat traps on the poles immediately under the houses protected nesting BB's and tree swallows. We would often find sprung traps indicating a coon had tried to get to the nest and then was turned back by the trap. Then last summer at least one coon got 'smart' when it realized that after the trap was sprung it could then go back up and rob the nest. The rest of the summer was a disaster as one after another boxes got robbed.

Without going into detail I declared war on the coons and significantly reduced their over populated numbers. To date there have been no coon attacks on nesting boxes this year.

Then, while walking early this morning I discovered a box where six bluebird eggs had been pecked and dropped out the entrance to the box. They were laying on the ground immediately in front of the box and none was broken, but all had been pecked. The nest inside the box was not touched.

My immediate suspicions are that the perpetrator was either a wren or a house sparrow. I tend to discount sparrow since this particular box is located at the far corner of our property with no buildings or yards closer than approx 1/4 mile away. We just don't see house sparrows out in this area.

We do see wrens in this area. We didn't used to have many wrens. Then about three years ago we had a wren nest in one of our boxes. Since we seldom saw wrens nest near us I permitted the wren and nest to stay. As a result our wren population has exploded and now we have wrens competing for the nest boxes all over. It has become a full time job removing the twigs and sticks that they are continually putting in all of the houses.

This represents the first attack of a bluebird house in this fashion for us. I am now concerned that it may be far from the last. There are legal ways to control the coon, sparrow and starling populations. Unfortunately, I don't know of any (legal) way to control the wrens.

Am I overlooking any other species of bird that may have been the perpetrator other than a wren or sparrow? Does anyone have any suggestions for legally controlling the wrens? Suggestions are appreciated.

Jeff

[Louis King//CUL Lou]

Jeff. Unfortunately, this sounds like a Wren to me. I've never had any problems with them, but have heard of this. As for controlling, or discouraging them from nesting on your place, I'm afraid I have no suggestions that would be legal. Sorry. Sure hate to see another enemy of the BB. I thought we were controlling their only flying enemy, the English House Sparrow. Oh suggestion, just came to me. Possibly if one were to find a house the Wren was building in, they might be able to use a trap, and take it to a different area. I'm NOT positive though that they wouldn't beat you home. I'm just not sure on this problem. CUL Lou

[Jeff Nelson]

Lou,

Unfortunately, it looks like I have another problem now - wrens! I was pretty sure that it was a wren attack when I discovered it this morning and Mark directed me to a website that confirmed it. You will want to visit the site to read up on the wrens, too. See http://www.sialis.org/wrens.htm

As you will learn it is very smart to watch out for wrens and to discourage them at the first sign that they are starting to use your nesting boxes. Once they 'learn' to use them they will fast become a big problem. I did not get rid of them when they first started coming around and boy I sure wish I had.

It is interesting how little trouble we had in the early years of our blue bird trail. The blue birds started using the houses shortly after we put them up and they multiplied and prospered rapidly over the first several years. Early problems with coons were solved by placing rat traps on the poles under the houses.

Now the coons have become 'smart' and the wrens have 'discovered' nest box living. The threats to our blue birds have increased in variety and frequency. The predator animals and birds learn and become a bigger threat over time. It is very disappointing to see what used to be a simple and straight forward housing design now require more and more modification and patrolling due to these increases in predators.

Jeff

[Louis King//CUL Lou]

Sounds like I definately need to start checking out the nest boxes, and try to discourage them that way. Thanks for the Sialis article. I'll read it more next weekend when I don't have to work ten hours a day. CUL Lou