2024 Bluebird Nesting Box Wrap-up
A Different Version of a Bird’s-eye View
By Volunteer Mackenzie Kaehler
The start of the 2024 McDonald Farm bluebird nesting season started in April. Three main bird species tend to occupy the 20+ nesting boxes placed at McDonald Farm in Naperville. They are Eastern Bluebirds, Tree Swallows, and the invasive European House Sparrow.
In variation from last year, some of the boxes were relocated to more open areas to discourage House Sparrows. A few boxes were removed from previous areas that were more heavily vegetated. This is because these boxes were rarely used and readily abandoned. The newer boxes placed in the more open areas more readily hosted many bird families over this season.
Unfortunately, many of the boxes this year housed multiple families of House Sparrows. Only one family, though, was successfully able to lay eggs and hatch them. Other House Sparrows were able to be discouraged. There were always one or two active Tree Swallow nests. Only one box successfully raised Bluebirds this season. House Sparrows and Tree Swallows were the majority of birds seen this season.
In the barns, and in contrast to last season, many Barn Swallows were nesting. Last season there were many House Sparrows occupying the barns. House Sparrows like to be near buildings, so many of the boxes near the barns were occupied by House Sparrows. This kept them away, to some degree, from the boxes preferred by the Tree Swallows and Bluebirds, who like the boxes more in the open fields. The Tree Swallows also liked the boxes closer to the ponds and wetlands. One Tree Swallow family occupied a back-to-back pair of boxes along with a House Sparrow. Red-winged Blackbirds are common in the fields, but they don’t use nesting boxes. Many hawks were also seen circling the fields consistently.
The goal of this season, as with every season, is to increase the Bluebird population. Bluebirds are native to Illinois and tend to be less competitive than the more aggressive House Sparrow. House Sparrows will attack and kill Bluebirds, as well as Tree Swallows, while in the nest. This causes a decrease in Bluebird populations. Without our native species, this causes a decrease in biodiversity. Biodiversity is the number of different native plant and animal species found in an ecosystem. The higher the biodiversity, the healthier the ecosystem. This is very important as without good biodiversity, the food chain will have gaps and can even close up certain lanes for other important species. It is very promising to see the return of many different native bird species this season. It was encouraging that we only had one violent casualty this season from the beaks of the House Sparrows.
Bluebirds continue to be a very important species to Illinois that seem to be making a comeback along with their other friends, like Tree Swallows.
Eastern Bluebird
