Stream valleys like the one that the Kanaranzi Creek occupies, provide natural corridors for the migration and movement of wildlife. The surrounding uplands are all planted in monoculture row-crops, so the pastures along the stream channels have diverse environmental mosaics that provide cover and are helpful as “stepping stones” for travel. However, the stream valleys also provide roadmaps to guide the long-distance fly-over birds, as well as the local birds that migrate away to the south for the winter. Down in the water and along the floodplain, there are also other animals that follow these corridor routes throughout the year.
The blackbirds have been around all Spring and Summer, but now in the Fall they gather in large and noisy flocks getting ready for the long fly south. They hang around in bunches while there are still leaves on the trees, but by the time the trees are bare the blackbirds are gone. In contrast, the eagles and vultures seem to be here year-round. These guys are scavengers. So as long as there’s dead meat available (like the piles waiting for the rendering truck outside hog barns) they don’t need to “migrate” very far….maybe a few miles up the Creek and back down to the Rock River.
One of the early signs of Fall are the geese that follow the Creek. Actually, it’s only the smaller family units that fly up the Creek in the morning and then return back downstream in the late afternoon. I think that they spend the night down along the Rock River and then return up the Creek valley for breakfast and lunch. In contrast, the long-distance fliers are big bunches that fly so high up that it’s hard to pick out individual birds and the flights look like thin strings against the blue sky. But, even at those heights, you can hear them calling encouragement to each other as they shift trading places to become the lead bird.
The U.S. Fish and Wildlife Service has identified a number of big river valleys in Iowa as corridors where migrating birds may encounter structures that pose collision hazards. These large streams are north-to-south thoroughfares used by both the long-distance fliers and the shifts of more local populations. In effect, the stream valleys are part of the connections between core areas of Summer residency in the north to the Winter retreats in the south. This “connectivity” is even more important for the animals that swim in the stream channels or walk along the floodplains.
This little guy caused a lot of excitement a few years back when cricket frogs were first identified in the oxbow wetland that occupies an abandoned channel meander in our pasture. They are listed as endangered species in Minnesota. Apparently they migrated up the Creek from the Rock River in Iowa and had not been documented in Minnesota for several decades. The Creek was a corridor that provided access to Minnesota, even though the site is only about a quarter mile from Iowa. Unfortunately, the drought early in the summer dried up the wetland and we didn’t see or hear any cricket frogs singing this year. Fortunately, we’ve not had any invasive species like flying carp or zebra mussels migrate up the channel in this wildlife corridor!
Several years ago, a neighbor found this paw print beside the Rock River a couple miles west of the Farm along the Stateline. Mountain lion sightings always cause a lot of excitement in the area because people are concerned about livestock. But, like coyotes, these peak predators are more interested in thinning the deer herds in the stream valleys, than killing domestic animals. Both mountain lions and coyotes tend to move along the corridors provided by big rivers and probably cover a lot of miles in their travels. There recently was a moose sighted in our area and although only one of the sightings was along a stream, that was probably his main route because people wouldn’t see him in the trees and brush that provide protection down on the stream’s floodplain.
The Nature Conservancy in conjunction with a number of Minnesota state agencies and nonprofit groups has mapped possible corridors (shown as colored bands) that might connect existing “core areas” (the small black squiggles) where there are viable prairie acreages. The big Minnesota River valley is the long black line trending southeast through the middle of the map, but the colored corridors in the southwest corner aren’t stream valleys. They’re glacial end moraine complexes that are too rocky and have rolling topography not conducive to farming. These southeast-trending corridors are connecting small patches of preserved prairie, rather than the huge core areas connected by big river valleys for migrating birds. However, valleys formed by streams of water flowing southwest off the front of the melting glaciers also form corridors. The Rock River and its tributaries fit that description. That includes the Kanaranzi Creek where it flows through Lone Tree Farm shown by the red star.
This post is the first in a transition series that will provide an introduction to a new venture. I’m planning to do a different blog that will continue the stories about the natural science and human history around Lone Tree Farm. But, the area will be expanded to include multi-county parts of southwestern Minnesota, northwestern Iowa, and adjacent stretches of eastern South Dakota. If you have any reactions to this idea, please share them in the comments section at the bottom of this page.