Story originally printed in the Winona Daily News or online at www.winonadailynews.com
Published - Sunday, April 27, 2008
Another chance for the passenger pigeon walk
Since participants had so much fun on Earth Day, Mississippi River Revival gives you a second chance this weekend to remember one wildlife species already gone and witness others amid critical habitat.
Flocks of millions of passenger pigeons once blotted the sun above the Mississippi, stretching from bluff-line to bluff-line, funneling like dark cyclones down to islands. Flocks turned trees slate-blue for miles.
One settler thought the massive flights sounded like a thousand venting steamboats, threshing machines and locomotives at once. Another sat amid a nest colony and found the doves uncannily fearless. Males cooed “bell-like wooing notes,” sidling against females, and both parents fed a milk-like curd to a single chick.
If passenger pigeons still existed, they might breed during late April at Aghaming Park and Preserve, so we’ll meet at noon Sunday at the Wisconsin end of the Wagon Bridge. Before hiking a trail through the floodplain forest to Osprey Marsh, we’ll gaze downriver and envision the pigeon colony Zebulon Pike encountered as he returned from seeking the headwaters, 1806.
“The most fervid imagination cannot conceive their numbers,” he said. “Their noise in the woods was like the continued roaring of the wind.”
A white canoeist noted a September roost near Wapasha’s Prairie in 1836, and Lafayette Bunnell heard oak limbs crash from the weight of an immense breeding flock circa 1843.
Passenger pigeons bred at different islands and forest-sites during different years, facing predators that remain at Aghaming today: mink, raccoons, peregrine falcons, owls, merlins, Cooper’s and sharp-shinned hawks.
Passenger pigeons did not defend chicks. They used an evolutionary strategy called predator satiation. Predators ate their fill while 90 percent of chicks emerged successfully from nests, says Birds of North America Online.
Passenger pigeons were decimated during the late 1800s, when harvesters disrupted nest colonies until reproduction ultimately failed. People shot, netted, clubbed and smoked out the doves. They poked, shook and plucked tender-tasting squabs from nests.
The first historical record of a massive nest abandonment derived from a colony near Mankato, 1860. Islands below Wabasha hosted the final massive nesting on the Upper Mississippi, 1871. The last large nesting anywhere occurred 50 to 130 miles northeast of Winona, 1881.
One of the final railroad shipments to eastern food and trap-shooting markets left Sparta in 1882.
We’ll also gaze at a quiet sandy road the city has considered protecting during the nesting season of snapping turtles, since vehicles have crushed eggs and turtles there. Snappers practice an ancient reproductive strategy currently at risk. It’s the wrinkled old-timers, not young snappers, who reproduce best. The older and larger snappers get, the more eggs they lay.
Snappers may reproduce 60 to 100 years, but when adults die prematurely, young don’t rapidly fill the void like mice or rabbits. A snapper in Wisconsin may take 10 to 12 years to grow a shell large enough to mate — 10 inches — said Robert Hay, Wisconsin DNR.
Snappers fall to plentiful hazards around Winona. Roads and railroads cause significant mortalities along the Upper Mississippi, and since females migrate to egg-laying sites without males, they suffer the largest losses, according to Mark Andersen, Wisconsin DNR. Riprap also foils turtles during travel. Smaller turtles especially get trapped between rocks and dehydrate or die other ways.
A busy highway near Aghaming — Highway 35 — is a death trap in some locations, said Hay. Habitat loss, nest predation, commercial fishing and trapping probably reduce snappers even more than road mortalities.
We’ll look for early turtles and also rusty blackbirds, North America’s most swiftly declining bird, according to the Patuxent Wildlife Research Center. Rusties foraged atop floating logs beside the path I call Prothonotary Trail last weekend.
Sunday may bring the trail’s namesake, the prothonotary warbler, a floodplain forest specialist in
40 percent decline since 1966. Ospreys may flap and flirt atop their nest, and if we’re really lucky, the state-threatened red-shouldered hawk might scream, or the spring’s first oriole might sing, or sandhill cranes may fly above a nest again.
The river shines uniquely during late April, reflecting the velvety burgundy of emerging maple leaves, green shoots on purple blackberry stems, cottonwood-tops soft and brushy, chestnut-colored oak buds. Sunlight pours through a mostly-open forest onto mirror-like sloughs while warblers, waterthrushes and kinglets sing amid the flyway.
We’ll absorb the tones and hues, discussing how to conserve wildlife in a world of channelized rivers where only 10 percent of Midwestern floodplain forests remain.
Bring binoculars. Kids get first chance to ask and answer questions.
Swanson chronicled nature at Aghaming February-June 2007 at www.riverbirdblog. com. Information in this story derived from The Passenger Pigeon, its natural history and extinction, A.W. Schorger, and The Use and Conservation of Minnesota Game 1850-1900, E.B. Swanson.
All stories copyright 2000 - 2006 Winona Daily News and other attributed sources.