On the Mississippi River, boundaries between states usually run down the middle of the main channel. (There are exceptions and a good map and observed shoreline features are the only way to tell).
When birds and the state line are in the main channel, then finding the main channel buoy markers is the task, as Benz explained in his Saturday post about scoters. The buoys are part of the U.S. Coast Guard's uniform waterway marking system and they assist boaters. Unintentionally, they help birders as well. These buoys are not positioned in the middle of the main channel for obvious reasons, and boaters in large craft know that to remain fully navigable they must stay between the red and green buoys. The red buoys are always on the left (port) side of the main channel while heading downstream and the green buoys are always on the right (starboard) side. One way to remember this is that port wine is red. That also requires knowing the port side is on the left, assuming downstream travel. When heading upstream, the red is on the right. That leads to another memory tool: "Red, right, returning." When you are returning back upriver, the red buoys are always on the right. If you are confused, then just remember this: Red buoys mark the Wisconsin side of the main channel and a green buoy marks the Minnesota side of it. Neither buoy type marks the middle of the main channel, which is where the state is. There are no buoys marking the middle of main channel on the Upper Mississippi River. Benz said the scoters were "on either side of a line connected by the red buoys." That means they were definitely in Wisconsin, and may have been flirting with the middle of the main channel and the Gopher state when they were on his side of the red buoys. Finding the approximate center of the main channel is a judgment but the buoys help. If you bird the river, are concerned which state birds are in, and especially if you are reporting unusual birds, this becomes crucial. Also look for "daymarks," larger fixed structures with lights that also show the river mile, as well as the left or right side of the channel (red or green lights and colors). One more tidbit: Red buoys are called "nuns" and green buoys are called "cans." They have different shapes, nuns with tapered tops and cans with square tops. This helps navigate without color. For this reason, red daymarks have triangular signs and green daymarks have square signs. The only other aid I can imagine birders using on the river, or other large water body straddling a state line, is a rangefinder. An accurate rangefinder would give the distance of birds from shore, and transferred to a map, might help judge where they are were. Regards, Jeff Dankert 908 Parks Ave Apt 158 Winona MN 55987-5330 (507) 454-0033 [email protected]
