Our suspicion is that black-crowned night herons have been nesting along the North Shore Channel. This bird is on the endangered list in Illinois. We have three known colonies around Chicago: Lake Calumet, Lake Renwick near Plainfield, and Baker’s Lake in Barrington. There are two other colonies along the Illinois River south of Peoria and another two near East Saint Louis. And that is it for the whole state.

The North Shore Channel brings water from Lake Michigan into the North Branch of the Chicago River. It is part of the system that turned the river around, directing its flow to the Illinois River rather than to Lake Michigan. The lake end of the channel is in Gillson Park in Wilmette, just down the hill from the Baha’i temple. From there it runs southwest to Emerson Street in Evanston, where it turns south, paralleling McCormick Boulevard and Kedzie Avenue in Chicago until it hooks up with the river just south of Foster.

Birders have seen the herons regularly along the channel throughout the breeding season, so on July 1 Alan Anderson, Allen Feldman, and I loaded my canoe on top of my car and set off to paddle the channel in search of them.

Alan suggested that we start at the lake and paddle all the way to Devon Avenue, since this would cover the area where most of the sightings took place. So we drove into the Sheridan Shore Yacht Club in Wilmette Harbor, unloaded the canoe, and put it in the water. We weren’t sure we would be allowed to do this, since the yacht club is a private place. But we followed the golden rule of gate-crashers–always act like you know what you are doing–and got under way without incident.

Unfortunately, things took a rather bad turn almost immediately. We paddled around the clubhouse and discovered that an enormous building sat athwart the channel dead ahead. The building houses the machinery that controls the flow of water out of–or into–the lake, and it also contains the controls for the lock that would allow boats to pass into the channel. Our problem was that this lock is no longer in operation. So, doing our best to act like none of this was a surprise, we hauled the canoe out of the water and portaged around the building.

Now, I should have known this building was there. I’ve seen it before, and I’ve even written stories about the structures that control our river. I need to start reading my own stuff more carefully.

The portage turned out to be rather long. Sheer concrete walls bracketed the channel beyond the lock, so we couldn’t put in there. We climbed some steps up out of the deep cut that holds the channel and found ourselves carrying the canoe through a golf course. Golfers gave us bemused stares. I said, “You haven’t seen a river around here anywhere, have you?” But I was thinking, “I may look ridiculous, but at least I’m not playing golf.”

The water level in the channel is a good 15 to 20 feet below ground level, but we eventually discovered a narrow path down the steep slope and slid the canoe down to the water. But even before we got launched, we knew we were too late. We saw two immature black-crowned night herons sitting on a steel railing on top of the sheer concrete walls just beyond the locks. They had already left their nests. Which suggested we wouldn’t find any active nests. We would see no young birds screaming to be fed and no trees spattered with the whitewash of several months’ accumulated droppings. We would, in short, not be able to verify nesting by black-crowned night herons. But it was a lovely day for a paddle, so why not enjoy ourselves?

There was a very slight but steady current in our direction, so we didn’t have to work all that hard at paddling. I was in the stern, Alan took the bow, and Allen sat in the middle and kept the bird list up-to-date. When the two of them were looking through binoculars to check out birds along the banks, all I had to do was use my paddle as a rudder and keep us pointing in the right direction.

We were far enough below street level to escape traffic noise, and the line of trees on each side of the channel hid all the obvious signs of civilization. The occasional bridges were the only intrusions, and their impact was softened by the barn-swallow nests that studded the beams on their undersides.

We compiled a list of 32 species of birds. All but two of those could be nesting along the channel. The two exceptions were great blue heron and ring-billed gull. We saw very young green-backed herons, obviously just out of the nest. We counted a half dozen belted kingfishers, and Alan pointed out two burrows in the bank that were likely nesting sites for that species.

The water toward the lake end of the channel had a slightly milky look, but seemed otherwise inoffensive. As we got near the Howard Street sewage-treatment plant, water quality seemed to take a sharp dive. Some weird smells began to rise, and instead of slightly milky, the water began to look nearly opaque. The outfalls at Howard Street were spewing a sudsy effluent, and when I accidentally splashed some water on my pant leg, I began to wonder if my jeans would dissolve.

Allen was our fish expert, though it didn’t take much expertise to identify the carp we saw along the way. They were thrashing around in the shallows near shore, laying eggs in the mud. Carp are yet another example of an alien species bringing nothing but harm to a new environment. Their constant thrashing and their bottom-feeding habits destroy the eggs of a number of native fish, and they also stir up so much bottom mud that they keep the water constantly cloudy. There is experimental evidence that even a muddy ditch like the Des Plaines River would run clear if there were no carp in it.

Allen also noticed a muskrat swimming along the bank near the lake end of the channel, and he identified the three turtles we saw. One was a red-eared slider, a nonnative species that could just as well be called Woolworth’s turtle. Presumably somebody got tired of having this one around the house and let it loose in the channel.

The painted turtle basking on a downed log is a genuine native species, and so is the snapping turtle we saw catching some rays on the bank. This may have been the most impressive sight of the whole trip. Allen said it was probably a female, because the females are generally larger than the males–and this beast was very large. Its shell looked as big as a garbage-can lid, and its thick tail must have been a foot long. We saw it just downstream from the Howard Street plant, and its size set us all thinking about weird mutant strains of reptiles feeding on toxics pouring out of our sewers.

As we drifted south of Howard toward Touhy, we disturbed a bird in the water near the bank where overhanging branches partially hid it from our eyes. It may have been a pied-billed grebe, but we couldn’t be sure. It didn’t fly; it pattered over the water ahead of us. It could have been a young bird. If it was a young pied-billed grebe, bred on the channel, that would be a second endangered species for this waterway.

South of Howard Street we also started to see trees at the water’s edge with large pieces of their bark stripped away. Here and there we saw small trees felled by something that had cut them down by chewing through them. Yes, indeed. Beavers. These industrious rodents, once nearly extirpated from this region by overtrapping, have made a major comeback. We have thousands of miles of drainage ditches in the farm regions of Illinois, and these have served as both homes and travel routes for the beavers that have recolonized the state. And now we have them living in Chicago waterways. They won’t try to dam the North Shore Channel. They will dig burrows in the banks, the entrances placed underwater for safety, and live on the trees that line the channel.

We saw 30 to 40 black-crowned night herons on our trip, but it was too late in the year to verify nesting for the species. Next year we will schedule our trip for late April or early May, before the leaves emerge. At that time of year we should be able to see the night herons building their nests.