Ask a Naturalist: What are those posts in the prairie?

This article was written by Emily Bowers, Minneapolis Park and Recreation Board Naturalist at North Mississippi Regional Park

It’s summer and the prairie has become a hot, grassy, sea of life. In this wide open space the plants have been diligently stretching skyward, toward that bright summer sun. Most prairie plants reach heights between 3-7 feet tall, creating a landscape full of habitat for local wildlife such as insects, birds and mammals big and small. Nestled amongst these impressive grasses and flowers in the North Mississippi Regional Park’s north prairie are a series of metal posts, eight of which are adorned with a wooden box on top. These boxes were created to encourage the presence of one creature in particular, the Eastern Bluebird.

A relative to the American Robin, and at one time nearly as common, the Eastern Bluebird is a member of the Thrush family with a striking blue back, rust colored breast and rounded white belly. They are a partial migrator, with a range that extends from the Rocky Mountains eastward, and from southern Canada to Central America. The Eastern Bluebird is a symbol of happiness and an early sign of spring, arriving to Minnesota in mid-March through April for a breeding season that runs through July. Unfortunately, for much of the 20th Century bluebirds were a rare sight. Many Americans had never seen one, and those familiar with them were sure of their inevitable extinction.

Eastern Bluebirds prefer open landscapes such as meadows, prairies, fields, pastures, golf courses, backyards or even city parks that have scattered trees for perching. They forage for food primarily on the ground, catching insects and other invertebrates much of the year and supplementing their diet with berries over winter. Bluebirds are able to see their insect prey from 60 feet away! Native Americans, and later early American farmers, utilized bluebirds to reduce insect pests around refuse piles, meat drying areas and farm fields by inviting them to these spaces with hanging houses. The houses attracted bluebirds because they are a secondary cavity nester. This means that their cup-style nests are built into cavities, but the birds are not strong enough to create the holes themselves. Therefore bluebirds depend on cavities excavated by other wildlife, such as woodpeckers and other natural cavity creators, or nest boxes placed by humans.

From 1920-1970 dramatic declines in bluebird populations were caused by many factors such as pesticide use, harsh winters, removal of dead trees, and an influx of domestic cats. However, the main threats were habitat destruction and competition. Large portions of bluebird habitat were lost due to conversion for human purposes, which greatly reduced available food and shelter resources. To add insult to injury, between the 1850s and 1870s House Sparrows and European Starlings were intentionally introduced into America. Both of these non-native birds are also cavity nesters that are extremely competitive and aggressive, quickly becoming bluebird enemies and devastating their success.

By the early 1900s bluebird enthusiasts were already advocating for more people to put out bluebird boxes. Numerous community-driven, grassroots efforts were established by the mid 20th Century to introduce nest boxes in good nesting habitat and establish bluebird trails containing hundreds of nest boxes. Restoration efforts in Minnesota included partnerships between the DNR Nongame Wildlife Program and Bluebird Recovery Program that sponsored workshops, published education materials and promoted bluebird houses. Minnesota now has one of the most successful bluebird recovery projects in the nation.

The eight nesting boxes in the prairie at North Mississippi are regularly monitored by naturalist staff to check if they are in use and to remove any unwanted residents. The plain metal posts act as trail markers to assist in navigating the path to the next box amidst a sea of towering plants. Take a walk along the prairie and see if any birds are visiting the boxes for yourself!

This summer enjoy the outdoors through drop-in discovery in your community! MPRB Environmental Education presents Nearby Nature, a series of self-directed, nature-based activities designed to enhance the experience of park goers of all ages while exploring parks in fresh ways. Nearby Nature features five different activities that will be visible in parks throughout the summer season:

  • Storybook Strolls – walk through a great story and a park at the same time, page by page.   
  • Natural Finds – learn orienteering on special courses designed for Minneapolis parks.  
  • Nature Quests – discover nature through scavenger hunts, challenges, informational signs and more.  
  • Guided Experiences – nature-inspired yoga poses, forest-bathing techniques and other prompts help your mind, body and soul tune in to a refreshing state of nature.  
  • Collaborative Nature Art – find and add natural objects to mandalas, collages, community collections and other artworks-in-progress at parks.

All Nearby Nature activities are free and no registration is necessary. There is nothing to print off or know beforehand, and all activities can be easily navigated without assistance. Just show up and be ready for fun, relaxation and inspiration! Rotating through parks every week or so. North area parks include: North Mississippi Regional, Creekview, Bohanon​, Victory, Cleveland, Perkins Hill, Jordan, Willard​, Hall​, Farwell​, Bethune, and Bryn Mawr Meadows.

Get updates on activity locations each week at the Minneapolis Parks Neighborhood Naturalist page on Facebook. Share experiences and photos through the hashtag #NearbyNatureMpls or send feedback to our email ​Visit the Kroening Interpretive Center Facebook page for more fun ways to connect with nature in our community this summer.

Minneapolis Park and Recreation Board program buildings remain closed to the public until further notice due to the impacts of COVID-19. The MPRB’s priority is the health and safety of our park visitors and our employees. The MPRB urges park users to follow park use guidelines: Do not visit parks or trails if you feel sick; take social distancing seriously, stay at least six feet apart from other park users not part of your household; and wash your hands immediately before and after visiting a park.

Visit or sign up to receive email updates at by selecting “COVID-19” in the “News Updates” section.

Do you have a question about nature in your own backyard? Then send it our way by emailing and it could appear in a future article.