If you've been out birding along the Wasatch front in the past couple of weeks you may have noticed a common migrant missing from the picture.  This August the Wilson's Warblers just aren't around like they normally are.  Usually the last week of the month sees the greatest influx of these migrants as they head south, but this year it hasn't been that great.  In eBird there have only been 2 reports entered all month in Salt Lake, Davis, Utah, Weber, and Box Elder County.  Compare that to the history for this species in Utah and you can see serious differences.  Check out the graphic below:

infographic by author

Well spring migration was late, summer was late, and that may very well be leading to a late migration.  Should be interesting to see what the next couple weeks bring, and if the height of fall passerine migration is a couple weeks behind.  On a side note, about two weeks ago in the High Uintas I saw about half a dozen migrating Wilson's Warblers... Maybe they are sticking to the high country this year!