A Now Rare House Sparrow at Our Feeder
In many places in North America, the House Sparrow is not rare. In fact, it can be so abundant as to be a nuisance. When we first moved here to central Illinois, we started with a few House Sparrows, but within 10 years, we had a flock of about 30 eating at our feeders every day. Five years ago, that changed and this is when the Eurasian Tree Sparrow arrived and established a presence in our back yard. One small flock of about 3-6 birds. As of this spring, we have about 25-30
Within a year of their arrival, we started to see a decrease in our numbers of House Sparrows until we rarely saw even one. It has been weeks since I have seen a House Sparrow anywhere in our yard, but this morning at our feeders, I saw a male. 
My observations of both sparrows represent change. The Eurasian Tree Sparrow is increasing its range – if you look at range maps on field guides published before 2015, this bird’s range is mainly the St. Louis, MO area. And the decrease of House Sparrows in our yard is not what normally happens. This is an aggressive bird that can out-compete any bird of its own size and also many larger birds for food and nesting sites. Change generally indicates something has been altered. So what has been altered that caused the decline in our House Sparrow population? Was it the arrival and increase of the European Tree Sparrows? I do not know. But this will be interesting to watch over the ensuing months and years and see what happens to both birds. If you are interested in these sparrows, see my Article: Eurasian Tree Sparrows and House Sparrows – Similarities and Differences.