My husband made this bluebird nest box in the spring and mounted it on a pole that is easily visible from our kitchen window. We had a pair of bluebirds move in within a couple weeks. We took joy in watching them fly in and out, first bringing grasses to build a nest. Later they laid eggs and raised a clutch. We saw them spend a lot of time flying around, going in and out, carrying insects and other delicacies, presumably for their young chicks. This went on for a few weeks.
Recently, we experienced just how cruel nature can be. House sparrows and wrens started hazing the bluebirds. It was rather traumatic watching the bluebirds come under attack after watching them raise a family.
I did some on-line research and discovered that this is quite a common occurrence. House sparrows and wrens frequently chase off bluebirds. They will even break the eggs, or kill chicks, and sometimes kill adult bluebirds, so they can take over the nest. They are even known to build their nest right on top of the bluebird bodies.
House sparrows are an invasive species. That means not native to the United States. Hence, they are not protected by the Migratory Bird Act. Wrens are native and so are protected. I immediately employed some of the deterrents that I read about to help our bluebird friends. I found instructions for something called a “sparrow spooker” and constructed and installed one right away. This consists of the metal strips hung from a strip of wood or twine. It can be seen in the photo above.
The sparrow spooker seemed to confuse the sparrows for a bit. I did see them or the wrens enter the house a few times afterwards, but other times they shied away. I was back the next day ready to continue battle with the avian invaders after doing further research. Apparently, if you install monofilament fishing line vertically along either side of the entrance to the nest box, sparrows, and hopefully wrens, do not like it. The sparrows and wrens cannot see the line and when they bump into it, it confuses and upsets them. Hopefully, enough so that it will keep them away. I did see a wren bump into the line and sit in a branch nearby tilting his head and staring at the offending area. Bluebirds, being insectivores, are thought to have better eye sight and can avoid the fishing line. That installation is also visible in the photo above.
Bird activity in general is less at the nest box today. I haven’t seen the bluebirds since yesterday, and the number of sparrow and wrens sightings is less too. I am hopeful that the clutch of bluebird babies grew up and fledged before the interlopers showed up. We did not find any baby bluebird bodies in the nest, nor did we find any on the ground in the surrounding area. My research says that bluebird babies fledge in 17-21 days. We had been watching the box for some time so it is possible that the young left to live out their lives elsewhere.
There is one last thing to try at some point in the future. My delving into sparrow habits unearthed the fact that they are territorial. They will not allow other house sparrows in the immediate area of their nest. It’s not the bluebirds per se that the sparrows take issue with. They just want the nesting site. I read that if you install two of the “bluebird houses” within 10 feet of each other, the sparrows will use one and bluebirds can nest in the other. The resident sparrows will not allow other sparrows to use it, leaving it open for the bluebirds.
This experience gave us pause to think. We put up a birdhouse, but who are we to say it is a bluebird house? The sparrows and wrens do not see it that way. And although it was upsetting when “our” bluebirds were driven off, it was nature at work. Should we be allowed to specify who lives in a birdhouse just because it is our whim? Tough choices.
And following, is a photo of one of our flowerbeds that was recently enlarged. Just so there is something positive to report today. I planted gladioli in it, so it should be bright and cheery soon!