North on the Wing

by Bruce M. Beehler

  As we toured a 925-acre demonstration area in the state forest and looked at a number of plots pre- and post-treatment, I gained understanding of what needs to happen here to generate fresh habitat for the Cerulean Warbler, Wild Turkey, and other local wildlife specialties. Proper management requires a combination of canopy thinning, midstory removal, and controlled burning. It is an expensive proposition, but it’s necessary to restart the natural disturbance regime that molded these forests in centuries past. Of course, there has been a fair amount of pushback from the general nature-loving public, who often see the existing forest as “pristine” and “natural,” although, of course, it is neither—it is the specific dead-end product of local human history, and it requires the human touch in order to provide the greatest benefit to biodiversity and birdlife. The public needs to learn that “disturbance” can be good as well as bad, depending on the scale and context.

  Certainly, the devil is in the details. A field study by Aaron Gabbe and colleagues in southern Illinois has demonstrated that the threatened Cerulean Warbler preferentially forages in an uncommon species of tree: the Shellbark Hickory. It is a large-seeded bottomland forest species that has difficulty recolonizing logged-over lands because its big seeds are not as easily dispersed as those of the many more common small-seeded species, such as the maples, oaks, and beech. Gabbe’s research suggests that fully functioning forest ecosystems require the regeneration of Shellbark Hickory in order to provide ecological benefit to the Cerulean Warbler. The take-home point: in some cases, good management means more than simply setting aside land and keeping it undisturbed and free of fire.

  After our field seminar, Fidler and I headed to Dixie Barbecue, a favorite local dining spot in Jonesboro, Illinois, where slow-smoked pork is sliced very thinly, grilled until slightly crisp on the edges, put on a warmed bun, and topped with a secret homemade BBQ sauce. That, with a cherry Coke, makes a fine downhome lunch. Aside from its barbecue, Jonesboro is famed as the site of the third Lincoln-Douglas debate, held on September 15, 1858. The seven “Great Debates” set Republican challenger Abraham Lincoln against Democratic incumbent Stephen Douglas in the race for a U.S. Senate seat in Illinois. Slavery (including the Missouri Compromise and the Dred Scott case) was the dominant topic in the debates. Unlike the soundbite format of current debates, the 1858 exchanges allowed one candidate to speak for sixty minutes, the second for ninety minutes, and then the first candidate was given a final thirty minutes to respond to the words of the second speaker. Lincoln lost that election to Douglas. Afterward, with free time on his hands, Lincoln collected and published the transcripts of the debates as a book, which was very popular and assisted with his election as president two years later.

  URBAN BIRDING

  My next field activity is scheduled for downtown Saint Louis, an urban birding hotspot. I have plans to birdwatch with local naturalists in one of the popular downtown parks of the city. Although I’m including city birding in this largely rural journey, I do not plan to stay in Saint Louis. Instead I’ll camp in Pere Marquette State Park, north of the city in Grafton, Illinois.

  Driving north on Interstate 55 toward the city, I encountered the first road-killed Coyote of the trip, plus a couple of road-killed Armadillos. Both species have been on the move in the East in recent decades. The Coyote has colonized much of the suburban East Coast, even appearing in city parks and preying upon local residents’ domestic pets. The Armadillo, confined to Mexico in the 1880s, continues its march northward into America’s heartland, but not without abundant road mortality. On a happier note, a Pileated Woodpecker, high in the blue sky, crossed I-55, the big black bird flashing its white underwings as it undulated gracefully from one woodland patch to another.

  On my way to Pere Marquette State Park, I passed through urban Saint Louis, which the summer before had been rocked by the Ferguson, Missouri, riots precipitated by the police shooting of Michael Brown. I made my way through downtrodden northern sections of Saint Louis toward the bridges crossing the Missouri and the Mississippi to Alton, Illinois. Passing the high, pale-gray limestone bluff on the Illinois side of the Mississippi, I followed the Great River Road twenty-one miles upstream to Pere Marquette State Park, where the Illinois River joins the Mississippi. It then became clear to me that Saint Louis is in this spot precisely because the three great rivers—the Missouri, Mississippi, and Illinois—come together here, smack dab in the middle of the country.

  Pere Marquette State Park, at eight thousand acres the largest in the state, has access to the Illinois River and a large boat basin. The park is lent a rustic ambience by a number of 1930s-era stone-and-log buildings built by the Civilian Conservation Corps, including a large guest lodge facing a set of pretty stone cabins. The tenting ground, a bit uphill, had trees, but overall this seemed a rather suburban park, influenced by its proximity to the big city just to the south.

  The next morning, May 14, I rose at 4 a.m. and drove downtown to meet my birding party: knowledgeable naturalists Christian Hagenlocher, Brad Warrick, Jacob Warrick, and Garrett Sheets, local residents who had answered my emailed call for birding guidance in the city. Together we headed for Tower Grove Park, in the middle of Saint Louis, and spent two hours birding for migrant songbirds. It was one of those cool and wet spring days that birders learn to appreciate—gloomy weather quite often produces excellent urban spring migrant birding. Small flocks of White-throated Sparrows foraged under every patch of shrubbery, their presence telling me that I was still near the front edge of the northbound wave of songbird migrants.

  Birding downtown parks is best during the spring migration, because cities’ vast expanses of concrete and asphalt make every small patch of green vegetation attractive to migrants at the end of a long night of flying. New York’s Central Park and Chicago’s Magic Hedge stand out as the most famous, but in fact most eastern and mid-western cities hold green spaces that bring in migrant birds, as well as birders, in numbers. Today the birding was good: our little team recorded fifty-four species, including a Black-throated Blue Warbler (a rare passage migrant this far west), vocalizing Olive-sided and Yellow-bellied Flycatchers, and a total of thirteen species of wood warblers passing through town.

  Later in the morning, I set the GPS for West Alton, a noted birding destination on the southwest bank of the Mississippi. Waiting at a downtown stoplight, I looked down an alley to see several feral cats hanging around what looked like a feeding station: a site periodically provisioned by some kindhearted person. Cat lovers maintain hundreds or thousands of feral cat colonies in cities and towns across the United States, an act of kindness with unintended consequences. Outdoor cats kill more than two billion birds each year in North America and can carry and transmit serious diseases, such as toxoplasmosis, to humans. Feeding feral cats does not halt their hunting of birds and mammals. Cats are efficient natural predators, and their introduction to novel landscapes has contributed to the extinction of thirty-three species of birds around the world. And for every wild bird killed, cats kill two to three wild mammals (chipmunks, rabbits, voles, shrews). The harm to vertebrate wildlife populations is substantial. Studies have also shown that feral cats live unhealthy, brutish lives, with none of the pleasures known to indoor cats properly cared for by their owners. It turns out that the trap, neuter, release, and feed movement is really not humane treatment for these creatures, which lead mean lives and which are destructive in urban and rural landscapes. The American Bird Conservancy, through its innovative Cats Indoors! Program, has worked for more than a decade to educate cat owners and cat lovers about the proper stewardship of their pets and to foster state and national policies that protect wildlife from the depredations of wild-roaming cats.

  ABC works on other urban/suburban bird issues besides cats, two of which are particularly important for migrant songbirds. The nighttime illumination of tall urban buildings leads to the maiming or death of many spring migrants, especially on foggy and rainy nights, as do lighted transmission towers. The
threat is exemplified by a kill of more than four hundred songbirds of twenty species, including many migrant wood warblers, at a lighted building in Galveston, Texas, in early May 2017. ABC is working with cities to alter building and tower lighting to reduce bird deaths. Reflective windows also kill many birds, especially in suburban habitats where windows face a mix of lawn and woody vegetation, and so ABC has worked with companies to create specialized window tape that discourages bird collisions. Cats, windows, and lighted buildings are just three of the threats that migratory birds face when passing through urban and suburban landscapes.

  The confluence of the Mississippi and Missouri rivers, on the northern verge of Saint Louis in West Alton, includes verdant wetlands and bottomlands, even though it is adjacent to a sprawling urban center. Because of the area’s flood-prone nature, the Army Corps of Engineers has created all sorts of impoundments and flood-control structures that, happily, are attractive to birds. After a brief visit to the Audubon Center at Riverlands, just north of town (highlight: Blue Grosbeak), I wandered about on what is essentially a peninsula between the two big rivers and ended up, without knowing where I was going, at Edward and Pat Jones Confluence State Park, where the Missouri and Mississippi meet. I walked out to the wooded point where these two streams of silt-laden water come together. It is awe-inspiring to stand at the narrow point of land where these great rivers collide, and where geography and history and nature come together.

  Birding on the wooded point yielded a Gray-cheeked Thrush, an Indigo Bunting, a White-crowned Sparrow, and both Baltimore and Orchard Orioles. Several vocal Warbling Vireos and Northern Cardinals hung out in the small triangle of Cottonwoods that forms the heart of the park. Out low over the muddy and turbulent Missouri, Chimney Swifts and Purple Martins hawked insects. It was gray and cool, damp and river-girt, and now I felt I was truly launching into the northern sector of my journey. Goodbye, southlands.

  At 5 p.m., back at Pere Marquette State Park, the rains had finally finished. The sun began to shine, and the black flies to swarm. They know exactly where to land and bite to generate the greatest effect. I slathered bug repellent on my neck and temples and behind my ears—the target zones of these devilish little dipterans. I looked through my food supplies and discovered that I had lost yet another loaf of bread to marauding Raccoons. When I had chased off last night’s thief, he’d also been sampling my tortilla chips.

  In the early evening, before cooking dinner, I tallied a Black-capped Chickadee here at the campground, a species confined to the northern half of the country. Tower Grove Park, downtown, hosts the southlands-dwelling Carolina Chickadee as well as some hybrids between the two species, but at Pere Marquette, it is all Black-capped. The local bird fauna was signaling my arrival in the North. I had now completed a bit more than six weeks out on the road—almost half the journey’s allotted time.

  NAVIGATION RIDDLES

  The thrushes that I had seen at Edward and Pat Jones Confluence State Park, and spotted in numbers elsewhere in the midcountry woodlands, are ideal subjects of field study because they are large enough to carry tiny radio transmitters on their backs, which allow researchers to follow the migratory movements of individual birds. This is a great way to learn about how songbirds navigate to their nesting territory in the North Woods.

  William Cochran and Martin Wikelski have conducted three decades of radio-transmitter research, and their studies reveal the basics of thrush navigation. After each night flight, northward-migrating thrushes stop over in woodlands and feed until their fat levels are restored to preflight levels (which requires several days). In spring, these birds have a remarkable ability to put on the fat reserves needed to power migration as well as to handle the future demands of establishing a breeding territory. Stopover birds forage in an area only about a hundred yards in diameter. At the end of the day, before departing on their next flight, the thrushes calibrate their magnetic compass based upon where the sun sets or upon the plane of the polarized sky light that they detect overhead.

  The birds migrate only at night, and only on nights when the air temperature is not too chilly and when the wind speed at ground level is less than six miles per hour. In flight, the birds beat their wings about six hundred times per minute. Their heart beats at around the same rate. They typically fly about thirty-five miles per hour (ground speed) but usually benefit from a tail wind. They fly until they deplete their fat reserves or until daybreak, whichever comes first, and then they drop down into another wooded patch with access to water.

  Night flights last as long as eight hours, and the birds travel as much as five hundred miles each night but typically only half that distance. Perhaps most remarkable is that the thrushes keep a constant magnetic heading during their entire migration up the Mississippi. Once the northward-traveling birds reach the latitude of their breeding habitat, they switch to eastward- or westward-trending flights to locate their preceding year’s nesting territory. The mainland migration (from the Louisiana coast to breeding habitat in Canada) takes on average about forty days, which includes about eight night flights and many additional days and nights of rest and foraging. The flight from Panama, where they winter, to Ontario entails 3.2 million wingbeats.

  Unexpected findings include the discovery that overland migration imposes only a moderate energetic demand on the thrushes. The researchers also found that birds typically stop migrating and drop into a woods upon encountering a cold front. Most remarkable of all is that migrating thrushes change their orientation to fly toward a thunderstorm when lightning is visible. The most likely explanation for this phenomenon is that the thrushes want to stop over in a site that has plenty of water available (which is likely if a thunderstorm had recently passed). The most important result of recent studies of thrush migration is that the birds can successfully navigate across the continent by using a set of simple migratory decision rules, rendering what at first appears impossibly complex into the realm of the understandable. Some mysteries remain, of course. For instance, once the songbird arrives at the proper latitude, how does it determine whether its natal breeding site is west or east of that point? Which GPS-like cue provides that information? That riddle remains for researchers to answer.

  EFFIGY MOUNDS AND THE BIRDS OF THE DRIFTLESS AREA

  I next travel north to the confluence of the Wisconsin River with the Mississippi, site of Wyalusing State Park, where I will camp for several days. Along the way I stop at the restored prairie at Wapello Land and Water Reserve in Hanover, Illinois. In the early nineteenth century, this patch of prairie was a Native American village headed by Chief Wapello of the Fox (or Meskwaki) people, and the archaeological site reveals two periods of occupation, the oldest tracing to 1050 CE. North of Hanover, a Red-bellied Woodpecker flies across the road in front of the car, reminding me that I am at the northern edge of the range of this nonmigratory southern species, which has expanded northward over the past half century.

  As I approached Galena, Illinois, in the northwestern corner of the state, I turned onto the Ulysses S. Grant Memorial Highway, which leads to the former president’s hometown through verdant rolling country, a mix of woods and well-tended agriculture, and descends the high sandstone plain to Galena. Looking down, I saw what seemed like a New England college town, its church steeples rising out of maples. The best historic aspects of old Galena have been preserved and restored—it is one of those small and picturesque rural towns whose economy has adapted to attract tourists who love pleasing scenery, restored old buildings, tranquility, and good dining.

  In midmorning, I arrived at the Wisconsin state line. The Mississippi has cut a deep valley here, and adjacent to the river the land is wooded and hilly; back up on the ancient elevated plain, away from the river, it is flat farmland. Here the farms were big and prosperous, each farmhouse surrounded by four or five major outbuildings. The neatness of the farms was impressive, but they were too tidy for my taste, one reason that on my way north I kept mainly to small roads nearer the r
iver, which were greener and less tame. A lot of Black Cherry trees were in bloom, and the leaves of the commonplace Black Walnut trees were just starting to unfold; many trees on the exposed ridgetops had not yet fully leafed out. Spring was only just arriving here, although it was already May 18. The radio announced an expected predawn low of 39°F for the 19th, and the northwest wind was starting to blow, which would slow the northward songbird migration.

  Wyalusing State Park perches atop a high bluff looking down on the deep valleys of the Wisconsin and Mississippi rivers, whose confluence lies just west of the park. I settled into a campsite set a bit back from the bluff, protected from the winds striking the northern face of the escarpment. As I erected my tent, I was greeted by the songs of Rose-breasted Grosbeak, Wood Thrush, and Tennessee Warbler. A female American Redstart gamboled about the campsite no more than a few feet off the ground, and a male Cerulean Warbler sang repeatedly in the forest canopy just above the picnic table. The birdsong was welcoming, but the approaching chilly weather was not.

  Cerulean Warbler

  In the afternoon, I visited Effigy Mounds National Monument in Harpers Ferry, Iowa, just across the Mississippi and upstream from Prairie du Chien, Wisconsin, the nearest town to the state park. Here, about a thousand years ago, Native American communities fashioned giant animal-shaped earthen mounds on the high plateau overlooking the river. Of its 206 surviving earth constructions from the mound-building culture, Effigy Mounds National Monument exhibits a range of examples, and I visited several of the most famous: Big Bear, Little Bear, and a line of simple conical mounds that resembles a necklace of beads, just back from Eagle Rock lookout. The stiff climb from the visitor center up to the main concentration of mounds was lightened by vocal songbirds in the woods, including numerous locally breeding Rose-breasted Grosbeaks and American Redstarts. Mature forest has grown up to engulf the mounds, which are scattered far and wide. The Park Service has cleared the mounds of woody vegetation and trees to make it possible to see the details of the ancient earth sculptures. One wonders what the environment looked like when these mounds were in active use. Were they set in woodlands or open country?