I’ve gone back to the spot I first found the great horned owl now several times, at the same time of the evening, and birded around there in the evening many more times to no avail. I did talk to someone down at the Loon’s Foot Landing ore dock who claims an owl comes around “once a year” and hunts from the ore dock. He said it hunts pigeons, and will sit on the dock to eat its kill. This is right across the street from where I saw the owl, so let’s assume it’s the same one. I’ve since looked around the area extensively for nests, and now have my ears out for fledglings, but no luck so far.
Let’s assume the great horned owl I found was an unsuccessful male. I don’t have much to go on for that assumption, and it very well could be wrong: I’ve never heard any calling in my block, and you’d think an unpaired male would be more vocal later in the season. I made a possible home range map based on the measured spring home range for unsuccessful males in Wisconsin: 279 ha (Petersen & Nehls 1979). I did the “full spring” range because I’m not sure when the ore dock sightings occurred. I also put the known locations at the western periphery, because several repeat visits didn’t yield a sighting of the owl (though this could be wrong because often the full home range isn’t utilized, especially in spring), so perhaps it’s found in those places infrequently because those locations are more toward the edge of where it hangs out.
I put the sightings at the western periphery so that the home range was more in the block.
Petersen, LeRoy R.; Nehls, Susan, Editor. Ecology of great horned owls and red-tailed hawks in southeastern Wisconsin. (Technical bulletin. (Wisconsin Dept. of Natural Resources), No. 111) Madison, Wisconsin: Wisconsin Department of Natural Resources, 1979. 63 pgs.