Ms Janislav and I are very amateur birders, so we were delighted to recently sight a bird known only in a very small portion of the U.S. The birds at the late-winter feeder were the usual crowd that day and it was only in passing that I noticed a particular House Sparrow that looked a little different. I watched it for quite a while and carefully noted the colors and dark patches. Then I went to my Peterson Field Guide.
Sure enough, this was a new bird - a Eurasian Tree Sparrow according to my 1980 vintage guide. The surprise came when I turned to the range map for this bird. The 1980 map showed a small blue dab of color along the Mississippi River in western Illinois. A note added, "Introduced from Europe 1870." Here is a bird easily mistaken for a House Sparrow. Both were introduced to this country nearly 150 years ago, but unlike its look-alike, this bird hasn't done all that well. Join us below the orange fluffy down for a closer look.
The House Sparrow had a head start, being introduced about 20 years before the Eurasian Tree Sparrow. House Sparrows were released in many eastern cities beginning with New York in the 1850-1852 period. The release of European birds in the U.S. seems to have been a common activity in those days and many of the introduced species were quite successful. Carl Daenzer imported the Eurasian Tree Sparrows from Germany and released them in Lafayette Park, St. Louis on April 25, 1870. By the time the Eurasian Tree Sparrows were released in St. Louis, House Sparrows had already spread from New York to the Mississippi River.
Both birds are correctly classified as weaver finches, not sparrows. A Eurasian Tree Sparrow is slightly smaller than a House Sparrow and is distinguished mainly by dark cheek patches, a narrow collar of white that circles the neck, and the lack of a black bib. Both sexes of Eurasian Tree Sparrow look alike. These four birds visiting our feeder show the distinguishing marks. An 2003
article in the Missouri Conservationist said that the farthest these birds had spread north was to the Iowa border, but now they have been sighted across
many areas of Eastern Iowa. Evidently where these birds share habitat with the House Sparrow, they are often forced out, so in St. Louis they have moved into the suburbs and countryside and are not seen in many urban areas where they used to be common. On our deck, however, the House Sparrows and European Tree Sparrows seem to coexist, possibly because there is plenty of seed to go around (except for the bird on the top perch).
Eurasian Tree Sparrows seem to defer to feeding House Sparrows. They also seem to prefer the tube feeder to feeding on the deck flooring. They have been daily visitors for several weeks, and have appeared in groups of up to 10 individuals. We wonder whether we have been seeing these birds for a number of years without realizing it. We wonder whether they will be back again next winter when the feeders go out again. We wonder whether our deck will become a Mecca for bird watchers. We'll keep you posted.
What's happening in your back yard as the equinox nears?