Unique among woodpeckers, Yellow-bellied Sapsuckers don't need dead trees for feeding and are also the only North American woodpecker with a true migration.
Photo by Kelly Colgan Azar
At the tail-end of the Common Nighthawk migration, birders in Wisconsin can still catch these birds through mid-October, though with waning numbers. The true peak nighthawk season is late August in Wisconsin, depicted in the eBird abundance animation which you can see below, dated August 31.
Photo by Putneypics FCC