“Yoo-hoo, anyone home?” I sing as I gently tap tap on the side of an Eastern bluebird nest box. I want to make my presence known before opening the door so any adults on the inside get a chance to fly out. They don’t mind me as long as I am gentle and move quickly. I’m getting ahead of myself; let me back up a little.
The Eastern bluebird is a cavity nester, meaning they use natural cavities, like old woodpecker holes in dead trees, for nesting. In the late 1960s, the Eastern bluebird population reached record lows. In 1978, the North American Bluebird Society (NABS) was founded to promote the recovery of bluebirds and other cavity nesters.
In 1986, Wisconsin created its own affiliate of NABS called the Bluebird Restoration Association of Wisconsin (BRAW). They estimated the Eastern bluebird population had declined by 90% during the preceding 50 years due to changes in agriculture practices, severe weather, invasive house sparrows and European starlings, as well as the loss of nesting sites.
BRAW’s mission is to increase the Eastern bluebird population throughout Wisconsin in many ways including building, setting up and monitoring nest boxes and expanding public knowledge and enthusiasm for the Eastern bluebird so people will have the desire and know-how to aid these and other cavity nesters in their own communities.
Why do we care? The Eastern bluebird is important not only for its beauty and spiritual meaning of hope, joy and rebirth, but also because bluebirds play an important role in protecting crops from insects. Farmers put up bluebird boxes around agricultural fields so the birds can feed on insects that could otherwise destroy their crops.
When I learned about the opportunity to monitor 14 bluebird nest boxes, I quickly raised my hand. I wanted to be a part of the effort to help this beautiful bird’s population grow. Other cavity nesters that I may encounter in my nest boxes are wrens, house sparrows, European starlings and tree swallows.
In a nutshell, this is what monitoring a nest box entails. Every week from March through August, I check the nest boxes. I record what I see, (i.e., the bird species, number of eggs, number of chicks) and then identify and fix any problems such as removing ants or wasps from the boxes. At the end of the season, I send in my records through regular mail or online. This data is analyzed to find population trends.
To help identify the bird species, the BRAW website has pictures to show what each bird’s nest is composed of, how it is structured and what each bird’s eggs look like. Bluebird nests are cup shaped and woven with fine grass or pine needles. Their eggs are pale blue or white with no spots.
Eastern bluebirds have one to two broods, sometimes three, each summer. I pay attention to when the chicks have fledged (left the nest), so I can clean it out before the female looks for a place to build her next nest. Bluebirds do not clean out their own boxes but are more likely to choose a nest box that is clean, whereas house sparrows and wrens prefer them not cleaned out. So it helps my chances of getting a bluebird to use a box if I clean it out when it is vacated.
Learning about the other cavity nesters is a side benefit. The tree swallows include soft, fluffy feathers in their nests. The territorial wrens will put a small stack of sticks, called a “dummy nest,” in boxes near their own to make them appear to be occupied. The aggressive house sparrows will build their nest on top of another bird’s nest, even with eggs and chicks inside.
Although it may seem that there are many things to learn about monitoring nest boxes, it isn’t hard. It is fun and rewarding. Imagine the joy of opening the box and seeing a nest, then eggs, then babies and then watching them grow. My heart grows along with them. Best of all, it is working. Due to thousands of bluebird nest boxes being installed across the country and volunteers monitoring them, bluebirds have made an incredible comeback.
If you are interested in helping bluebirds, please visit the BRAW website at https://www.braw.org. It will include everything you need to know to get started and provides contacts, real people, to support you along the way. Even better, ask a friend to join you or pair up with someone already monitoring.
Perhaps in the near future, it will be you tap tapping on the side of a nest box, singing: “Yoo-hoo, anyone home?”
Lisa Jansen is a Wisconsin master naturalist, nature writer and award-winning photographer. She specializes in raising awareness of birds and butterflies of the Midwest.
Monitoring bluebird nest boxes helps birds thrive
