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By Jerry Sullivan

The place the National Park Service calls Inland Marsh is a complex landscape of high dunes and broad, low marshlands. It is a remnant of an earlier stage in Lake Michigan's development. When the winds were piling up these dunes the water's edge was about a mile south of the present shoreline.

Inland Marsh is part of the West Beach Unit of the Indiana Dunes National Lakeshore. Between it and the present shore are U.S. 12, a set of railroad tracks, Long Lake, and the high dunes and interdunal ponds of West Beach. The upland portions of Inland Marsh are covered with an oak savanna, and black oak is the most common tree. A rich understory combines prairie species like little bluestem and switchgrass, southern forest shrubs like sassafras, and northern species like blueberry. These black oak savannas growing on sandy soils are among the distinctive features of the vegetation of the Indiana Dunes.

I've been very fond of Inland Marsh for a long time. Thirteen years ago I did my first surveys on nesting birds there, getting a taste of an activity that now seems to have taken over much of my life. Doing censuses is obviously a seasonal project, but organizing them and compiling them can eat up most of the year.

I knew almost nothing about savannas in the spring of 1983. In those days prairies were the center of attention. We were studying prairie remnants and restoring prairies on old fields or on lands that had been invaded by box elders and other low-status woody vegetation. You could say there was a lot of generalized antitree feeling around, and even oaks--now objects of almost druidic admiration--were looked on with some suspicion.

I took a walk around Inland Marsh last Saturday, and what I saw brought back some memories and also raised some interesting questions for future study. Some weird stuff was still present, like the ancient car hulk that is slowly rusting away between steep sand hills. It must have been a real project getting that thing through the deep sands to this remote spot. You wonder why anybody would want to go to all that trouble just to get rid of a car.

When I first surveyed Inland Marsh I was most interested in the possibility of finding some neat wetland birds. I did find--or at least hear--one such marsh species. Twice in the predawn darkness I heard the unmistakable call of the king rail, a very nice bird indeed. But in my fantasies I was finding nests of king rails or maybe the female (queen rail?) slipping through the reeds accompanied by eight or ten downy chicks. Just hearing the bird off in the distance was way short of the experience I was after.

Aside from the distant rail, the wetlands produced very ordinary species, mostly redwings and marsh wrens. But the savannas, the upland portions of Inland Marsh, were beginning to tell me a story, though I didn't fully recognize it at the time. The story was about the birds of savannas, the avian community that lived in the landscape that occupied a major portion of northeastern Illinois before settlement. Nearly all that landscape has been destroyed.

The story of its bird life, like the story of its plant life, has to be assembled from various sources, and Inland Marsh was the first of my own sources. Scarlet tanagers were part of the story. My estimate was that four or five pairs nested there in 1983. At the time I was somewhat surprised to find them in such an open situation. Not only are the trees scattered, but the steep slopes put the crowns of adjacent trees at very different levels, making the canopy seem even more open. I expected tanagers to live in dense forest. However, all the books do say that these birds have a strong affinity for oaks, so maybe that was the attraction.

Inland Marsh was also the first place I heard the nest call of the Cooper's hawk. This high-pitched ki-ki-ki-ki is a sound they make only around their nest, so just hearing it was enough to confirm nesting. This species is scarce in most places. It is on the endangered list in many states, including Illinois, so finding a pair nesting is a big deal. Again I was somewhat surprised to find this species in such an open situation.

I would be much less surprised to find either of these species there now. Now we are thinking in terms of savanna birds, and both the tanagers and the Cooper's hawks seem to be candidates for the savanna bird list. You can see some logic in that in the case of the hawk. It is primarily a bird eater and typically perches quietly on a limb while keeping an eye out for movement below. The open understory of the savanna offers less cover for potential prey than the shrubbier conditions of a forest.

Down at ground level at Inland Marsh I found bobwhites. Our only eastern quail is essentially a southern species that hits the northern end of its range at the Indiana Dunes. In the pine forests of the southern coastal plain this species is typically found where soil conditions--and frequent fires--produce a sparse understory. Another prime candidate for savanna bird status.

In 1983 Inland Marsh had not been burned in some time, and portions of it had been taken over by thickets of aspen. In those dense thickets I found yellow warblers, yellow-breasted chats, towhees, field sparrows, and other species of brush birds. Except then I wouldn't have called them brush birds. I would have called them edge birds and assumed they were there because they like being at the edge of groves of larger trees. Now we realize that brush is the attraction and that these birds will find islands of brush out in the middle of a prairie. They don't actually need edges.

We are thinking a lot about the place of these brush birds in our natural areas. As a group these species are in some trouble because their favored habitat is so dependent on human intervention in the landscape. Most available brushy areas were once something else; they're former woods or old fields that are simply passing through a brush phase while we figure out what to do with them. You can get some emotion behind a campaign to save the prairies or preserve the stately oak woods. But a campaign to save brushy thickets somehow doesn't seem like the sort of thing that would inspire much passion. Most of our ecological restoration efforts involve removing brush--usually exotic species--so probrush opinion is hard to find.

On my visit to Inland Marsh last Saturday I did notice some changes in the landscape, changes that are probably the result of fires. There have been prescribed burns in the area in the past decade, and I believe there was one wildfire as well. The fires and, I suspect, some cutting have reduced the area covered by the aspen tangles. This means less habitat for the brush birds.

My impression was that more prairie plants are growing at Inland Marsh now than were there 13 years ago, but this is only an impression. The most startling change was the presence of dense thickets of black oak on many of the hillsides. Fires often kill the aboveground parts of trees, but the roots can survive the flames. In the spring following the fire these roots produce new shoots--often many new shoots. The presence of many trees with multiple trunks is a strong clue that a hot fire burned through sometime in the past.

The young black oaks at Inland Marsh are virtually all multitrunked. They range in height from less than 2 feet to about 15 feet, and their shrubby shapes form lovely brushy thickets. I found this rather startling because restoration efforts over the past couple of decades have usually involved removing brushy thickets so oaks can get enough light to reproduce, but here the oaks were the brushy thickets. It was a real treat to see them aggressively taking over the landscape.

Next June I will have to go back to find out if brush birds are nesting in these oak thickets. If they are we could have a solution to a vexing management problem. We tend to think that management--especially fire management--will produce a landscape of prairies alternating with stately groves of large oaks. The flames will keep down the brush, reduce the understory, and maintain the open oak groves that early travelers encountered in northeastern Illlinois. But that vision leaves no room for the brush birds. Inland Marsh suggests that the effects of fire can be more varied--that fires can produce brushy tangles as well as destroy them. And that there will be space for yellow-breasted chats in a restored landscape.

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