A New Sparrow in Central Illinois

Cleon and I live in central Illinois, and older field guides and online range maps, especially those created before 2012, usually do not show this area as part of the Eurasian Tree Sparrow’s distribution. Unlike many local birds, the Eurasian Tree Sparrow is not originally from North America. It was introduced near St. Louis and gradually established populations throughout the city and surrounding suburbs.

More than two decades ago, a small group of these sparrows appeared in Petersburg, Illinois. I know this because one of my cousins, who lives near Petersburg, noticed them visiting her bird feeders. Around five years ago, I began seeing them at our own feeders as well. At first, only a few individuals appeared, usually two or three birds. Over time, their numbers increased, and now we seem to have a stable population of roughly 15 to 20 Eurasian Tree Sparrows living around our property.

These birds remain in the area throughout the year, meaning they are breeding locally and surviving the winter months here. Interestingly, their arrival seems to have coincided with a decline in the number of House Sparrows in our yard.

Possible Impact on House Sparrows

We have lived at our current home for nearly 20 years, and House Sparrows were present from the very beginning. Their population grew quickly, increasing from a small group of around six birds to more than 30 individuals.

However, after Eurasian Tree Sparrows appeared about five years ago, the number of House Sparrows gradually dropped. Eventually, we were seeing only two breeding pairs in our backyard. By the middle of summer 2023, even those pairs disappeared from our feeders, bird baths, and yard.

During an especially cold period in January 2024, when temperatures dropped to around 0°F or lower, about eight House Sparrows returned briefly to the feeders. Once temperatures warmed back into the 20s, they vanished again.

Did the Eurasian Tree Sparrows force the House Sparrows away? Did they compete more successfully for nesting areas? Did they take over feeding territories? At this point, we simply do not know. House Sparrows are already known for their aggressive behavior and determination, so the idea that another sparrow species could outcompete them seems surprising. However, it may be exactly what is happening.

Identifying Eurasian Tree Sparrows Among House Sparrows

If you have House Sparrows near your home or in a favorite birding location, do not automatically assume every sparrow in the group is a House Sparrow. Eurasian Tree Sparrows appear to be expanding their range, and they may be present in places where people do not expect them.

One of the easiest ways to identify them is by examining the male birds. Eurasian Tree Sparrows have a noticeable black patch on their cheeks. If you see this marking, you are looking at a Eurasian Tree Sparrow rather than a House Sparrow.

Some bird references suggest that Eurasian Tree Sparrows and House Sparrows do not mix in the same groups, but that has not been true in our yard. We regularly see both species together on our platform feeder and on the ground beneath the feeders.

This creates a challenge for birdwatchers because real-life bird behavior does not always match what is written in field guides.

Differences Between Eurasian Tree Sparrows and House Sparrows

Male and female Eurasian Tree Sparrows have nearly identical appearances, unlike House Sparrows, where males and females look very different. The Eurasian Tree Sparrow can easily be confused with a male House Sparrow because of their similar coloring and markings.

When viewing them from behind, I find it nearly impossible to distinguish the two species. The best identifying feature is the dark cheek spot found on Eurasian Tree Sparrows.

There are several other differences as well. House Sparrows have a gray stripe on the head, while Eurasian Tree Sparrows do not. Eurasian Tree Sparrows have a black chin but never develop the large black throat patch known as a bib.

House Sparrows also have a black chin, but their bib is mainly visible during spring and summer. In autumn and winter, the bib becomes much smaller or may disappear almost completely.

A Changing Sparrow Population

Many bird species around the world are experiencing population declines, and the House Sparrow is one example. At the same time, some species are expanding their numbers and moving into new areas.

The Eurasian Tree Sparrow demonstrates how bird populations can shift over time. Its growing presence in areas outside its traditional range shows that nature is constantly changing, and careful observation can reveal unexpected developments happening right in our own backyards.