by Tim Vargo
Quick quiz: Dorothy, Toucan Sam, and the three wise men. What do they all have in common? They all had a destination and something to use as a guide. Dorothy had the yellow brick road, Toucan Sam had his nose, and the Wise Men had the star of Bethlehem. Interestingly, our Riverwest neighborhood also holds a “guide” that through the millennia has been used by trillions: our own Milwaukee River. For thousands of years, the Milwaukee River guided the boats and hiking trails of Native Americans, including the Winnebago and Potawatomi. Later, it guided the likes of Marquette, Juneau, Kilbourn and other historical figures by boat, by foot, and by wheel — it’s no coincidence that Water Street is never more than a stone’s throw away from the river. With the rail boom a few decades later came a railroad bed used by Chicago & Northwestern built alongside the river. Today that railway bed (now paved over) guides many of us to work on our bicycles, in-line skates, and cross-country skis. There’s no doubt that this river has played a huge part in history. But I mentioned that the river has served numbers in the trillions. Unless you’re talking about McDonalds, numbers like that can’t be served without including the nonhuman customers of the river: the wildlife. The Milwaukee River has obvious importance in guiding migrating and dispersing fish, frogs, insects, and other animals that are anatomically tied to the water. Removing the North Avenue dam, for example, allowed native perch, trout, and bass to return to our stretch of the river. The river also guides plant seeds (willow, joe-pye-weed) during dispersal; it guides bats and swallows to swarms of hatching insects; and it provides cover while guiding dispersing turtles. Like humans, animals and plants use the river as a right-of-way for transit, often “settling” along stretches where there is abundant food and protection. To me, however, an entirely new level of importance and grandeur surfaces when considering the river’s role in bird migration. Every spring and fall, thousands of birds from as far away as South America use our river for guidance during their journey between their summer and winter homes. Some, like geese, swallows, and kingfishers use the “airspace” above the water. Others, like warblers, kinglets, and tanagers fly through the vegetation alongside the river (sadly, often by necessity because the surrounding land is developed). The importance of the river as a green corridor was never more evident to me than last May, when the citizen science team at the Urban Ecology center erected mist-nets in Riverside Park as part of a national effort to monitor bird populations. As luck would have it, Milwaukee was blanketed in a thick fog, forcing migrating birds low to the level of our nets. We were inundated with birds in striking spring plumage, including rare vireos, warblers and thrushes… so many that we had to close our nets early because they were flying into them faster than we could process and release them. What’s astonishing is that I later saw the list of birds captured that same day at Riveredge Nature Center, a 350-acre preserve 30 miles upstream, and their species list matched ours almost exactly! This is very strong evidence that the river was being used as a migration corridor (and that you don’t always have to leave the city to see beautiful wildlife). Internationally, development is creating landscape mosaics of forest patches, agricultural land, and concrete. This hinders and often prevents animals from carrying out seasonal migration and dispersal, decreasing gene flow and territory size and increasing the chances of local extinction. Because many animals refuse to leave green patches, even to cross a road, many conservation efforts today involve connecting patchwork habitats with corridors of green space. One of the largest conservation projects in history, for example, involves an international effort to link all of Central America with a green corridor. Closer to home, Friends of Milwaukee’s Rivers (FMR) has launched the Milwaukee River Corridor Project to raise awareness of the importance of a healthy river corridor, not only for wildlife, but for clean water and erosion control. If you would like to become involved with efforts to protect and monitor the health of the Milwaukee River, please call the Urban Ecology Center (964-8505) or Friends of Milwaukee’s Rivers (287-0207).