– November 27, 2009 –
A panoramic view of Chautauqua National Wildlife Refuge opened before me as I stood on the observation platform at the bluff edge. Looking directly west, expanses of open water, floodplain forests, and blue skies dominated my view; the Illinois River was obscured by the intervening forests, and beyond the river was another large floodplain lake called "Thompson Lake." Since it has been my experience from previous years that the waters of Lake Chautauqua in late autumn would be teeming with waterfowl, with my binoculars I took a quick sweep of the wide view. But surprisingly, except for a small group of mallards, I saw few waterfowl. This I found to be strange indeed, especially in late November; and so, I decided to sit on a nearby bench for a while, and hope that other birds might show up.
After five or ten minutes, a small group of greater white-fronted geese flew over the refuge and continued onward to the northeast. Soon a few Bonapart’s gulls passed, alternately flying and diving into the water. But during my observation period, other than one fast-moving group of five common goldeneyes, a single bufflehead, two American black ducks, and twenty Canada geese, this large waterfowl refuge continued to seem rather empty of waterfowl. But it made me wonder what might be happening at Thompson Lake. Was the waterfowl migration simply in a regional slump, with few ducks anywhere, or was there a difference between bird use of these two floodplain lakes. Of course, the only way to find the answers would be to immediately travel to Thompson Lake.
Though Thompson Lake was about three miles away from Chautauqua Refuge’s headquarters by line of sight, to reach it I first had to drive six miles south to Havana, cross the Illinois River, and then drive another two or three miles northward on state route 78, before finding a place to pull off of the two-lane levee road, just beyond reach of the rather constant highway traffic. I did not say "safe place to pull off" because there really is no such thing on SR 78. The busy highway traffic on the levee road seems to be mostly composed of folks engaged in serious travel, not slow-moving wildlife watchers looking for rare birds. So just before reaching one of several steep exit lanes that abruptly lead, at right angles, off of the highway levee, I quickly checked my rearview mirror, to make sure I was not being tailgated by a massive semi truck, and turned off the road. The exit ramp was muddy, soft, and steep; and even with a four-wheel drive vehicle, I was not confident that I could make the climb back up the levee. So I stayed parked near the top, just beyond the highway pavement. (It should be noted that wildlife viewing on Thompson Lake can also be accomplished at the boat launching area a bit further north on SR 78.)
But what I saw next almost allowed me to forget all about automobiles, loud pickup trucks, loud motorcycles, and semi trucks. Thompson Lake, nearly two miles wide and three or four miles long, seemed to be literally bank to bank full of waterfowl! There were thousands of waterbirds in view in every direction, as far as I could see. American coots were overwhelmingly the most abundant species. Ruddy ducks and ring-necked ducks were also quite numerous, though much less so than the coots. Northern shoveler, gadwall, canvasback, lesser scaup, pied-billed grebe, and horned grebe were also present. The contrast with Lake Chautauqua could not have been greater.
Later, as I waited for a break in the fast-moving vehicles so that I could safely enter the stream of highway traffic, I began to think more in depth about what I had just witnessed. Why was Chautauqua Refuge so little used compared with Thompson Lake? I felt certain the answer involved factors such as habitat quality, habitat structure, and food availability, or a certain combination of these and perhaps other factors. Of course, one major factor, the "elephant in the room," is the Illinois River itself. Thompson Lake is protected from the river’s degrading influences1 by a massive levee, while Chautauqua Refuge is frequently connected to the river through a system of spillways and gates. At any rate, because these two floodplain lakes are part of my regular route for making natural history observations, I hoped to answer my own questions one day soon.
Illinois River (left), levee, Thompson Lake (right), in 2009.
Chautauqua Refuge spillway with flooding river, in 2007.
1 For more information on the Illinois River, see the "River Reading List" in the "Categories" section on The River Landing’s home page (left panel).