Late Summer Adventures
August and September exhibit the first signs of transition to the low light months ahead. Birds are migrating, insects are reaching their populations peaks, and plants are setting seeds. This time frame is perfect for the naturalist to experience the state's natural fecundity. GNW suggests a few ideas for late summer adventures.
Shallow rivers: Late summer is normally the time when river flows reach their lowest point during their annual cycle. Walking in the very shallow areas, the naturalist can find freshwater mussels of many species. The Mississippi River watershed harbors are tremendous diversity of mussel species. Rocky areas with abundant sand, shallow riffles, and even sandy backwater areas harbor many of these speices. Look for clam-shaped rocks of lighter colors just emerging from the sandy substrate or even tracks in the shallower sands. These signs can lead to mussels and an understanding of the great diversity Wisconsin's rivers contain. Many of these mussel species can live for decades. After observing them, place them back in the location, you found them.
Wisconsin's Deserts: A few places in the state have the characteristics of a true desert. Many species have seasonal patterns of habitat use similar to the American southwest. These species avoid the scorching sands during the mid-day summer heat and become more active in the evening or at night. Other species burrow underground during the day and we even have species that estivate during the hottest part of the summer, thus putting on most of their growth in late spring and early fall. Several insect species, especially grasshoopers, have very disjunct populations - residing in the southern great plains or along the Atlantic Ocean dunes, and then somehow finding their way to small habitat patches in Wisconsin. Cacti and other succulent plants conserve water through their specialized leaf structures. Excellent opprtunities for observing these desert are found at the Spring Green Reserve SNA, Blue River Sand Barrens SNA, and the Lower Chippewa River SNA.
Fall Bird migration: The fall migration of birds in Wisconsin is much more protracted than the spring migration. Migratory bird movement occurs from late June through early January, although the peak numbers move through from mid-August and September. Many species can appear randomly, however some are more predicatble. GNW suggests the naturalist pay attention to these features.
Powerlines in farm and field country can have hundreds of swallows of 6 species congregating in August. By Labor Day, Barn Swallows and Tree Swallows make up the vast majority.
Keep an eye out for migrating Common Nighthawks silently coursing their way south at dusk between mid-August and Labor Day.
Watch the trail sides on woods paths during the first two weeks of September for migrating thrush species. They are most often seen immediately after a cold front drops rain and the temperature.
Visit sites near Lake Michigan. The northwest winds tend to blow species towards the great lake, but they are reluctant to cross. Thus, high numbers congreagted in these locations.
Consider joining the Wisconsin Society for Ornithology for their annual Jaegerfest. This event occurs near the third weekend in September at Superior. In most years, visitors from the high Arctic ,such as jaegers, scoters, Sabine's Gulls and loons are found.