Mid-September is a good time for grassland migrants in the Chicago area, like Sedge Wren. Photo by Josh Engel.

Chicago in mid-September is a good place to see Mourning Warbler. Photo by Josh Engel.

Mid-September is the peak of fall warbler migration. We will undoubtedly see Blackpoll Warbler, one of the classic "confusing fall warblers," giving us a good chance to learn about their identification. Photo by Josh Engel.

Northerly Island is both a great birding spot and a great place to see Chicago's famous skyline. Photo by Josh Engel.

We won't miss opportunities to see the intersection of birds and architecture as the opportunity presents itself. This mural, featuring Red-headed Woodpecker and Yellow-headed Blackbird, is by Collin van der Sluijs. Photo by Josh Engel.

A common migrant in Chicago. Photo by Josh Engel.

If conditions are right, we will do some hawkwatching, which could yield some sleek Merlins. Photo by Josh Engel.

Sneaky Nelson's Sparrows are always hard to find, but we have a chance to find them along the Chicago lakefront. Photo by Josh Engel.

If conditions are good, we'll spend some time looking for shorebirds. The beaches can be a good place to find them. Photo by Josh Engel.

One of Chicago's rarer migrants, we might get lucky and see this skulking sparrow in one of the lakefront migrant traps. Photo by Josh Engel.

Birds aren't the only animals migrating at this time of year, bats are, too. We may get lucky and find a roosting bat. Photo by Josh Engel.

Cape May Warblers are more common in fall than spring in Chicago. Photo by Josh Engel.

When conditions are right, Chicago's beaches, especially Montrose Beach, can be good for shorebirds. Photo by Josh Engel.

We'll need some luck to see Baird's Sandpipers, which are mostly through Chicago by mid-September. Photo by Josh Engel.

Photo by Josh Engel.

Bobolinks can sometimes be found in grassy habitat along the Lake Michigan shoreline in September. Photo by Josh Engel.

Photo by Josh Engel.

One of the more common migrants in September in Chicago. Photo by Josh Engel.

Chicago has a stunning mix of historical and modern architecture, often in close proximity. Photo by Amanda Zeigler.

A classic of mid-century architecture, Marina City sits right along the Chicago River. Photo by Josh Engel.