by Mark Sparky Stensaas
My hands were frozen and stiff. Clutching my binoculars was painful, but oh so worth it, as a rare ocean-going seabird—a parasitic jaeger—was flying low over Lake Superior, right off Duluth's Park Point. The jaeger banked and got on the tail of a ring-billed gull, sticking to it like a fighter pilot. The dogfight continued a hundred yards offshore. Jaeger, German for hunter, is an appropriate name for this aggressive gull-like bird that makes a living by harassing gulls into vomiting up their last meal. A few individual jaegers show up at Park Point every fall.
Remarkable birding is just one of the attractions for me and other visitors to the world's longest freshwater sand spit. Combined with the 3-mile-long Wisconsin portion, the entire spit is nearly 10 miles long, perhaps the largest and longest freshwater sand spit in the world.
How did this sandbar form? It is the natural outlet for the St. Louis River. Late in the last ice age, raging glacial meltwater of the ancestral St. Louis River deposited sand, silt, and clay into the future Lake Superior, which was blocked to the north by receding glaciers. Wave action in shallow waters on the lakeside, combined with river-mouth sand deposits, formed several sandbars over the millennia. Park Point is the most recent one. Today the St. Louis River continues to deposit sand at its mouth. And waves meeting the beach at an oblique angle (called longshore drift) bring more sand from the south shore sandstones. Wind and wave action then move sand around to form dunes.
You can drive only so far down the point, and then you must hike. Every time I crest the 20-foot-high rolling dunes and look out over the wide beach and Lake Superior, I think: "Am I still in Minnesota?" The scene is more reminiscent of Cape Cod on the Atlantic Ocean than of a north woods lakeshore. The reason for this resemblance, beyond the sand dunes and endless water horizon, might be the grass that holds the dunes in place.
American beach grass (Ammophila breviligulata) is an iconic dune grass of the Atlantic seaboard. The knee-high grass with wide, flat blades flows and ripples in the wind. Though it does grow on other Great Lakes beaches, this species is limited to habitats of shifting dune sands and reaches the westernmost point of its native range in North America on Park Point. This grass thrives in sterile sand habitats and can spread across 10 feet of dune in one year.
"In fact, sand burial stimulates the plant," says Department of Natural Resources botanist Rebecca Holmstrom, "and its shoots respond by growing vertically as the dune gets higher."
Without beach grass anchoring dunes, the sand would endlessly drift and dunes would migrate, eventually burying roads, airplane runways, and houses, says DNR botanist Ethan Perry. Erosion of these dunes was once a serious problem, due to trampling of vegetation by beachgoers. Since 1985, the Park Point Community Club has been planting more beach grass to help stabilize the shifting sands and has fenced off fragile dunes near the most popular swimming beach.
If you're getting sandblasted on the dunes and beach, duck into the wooded cathedral of old-growth red and white pines, which is just beyond the Sky Harbor Airport. It's quiet. Wind sighs in the tops of ancient pines growing out of old sand dunes.
The open understory is dotted with juneberry, pin cherry, and chokecherry. The sandy floor hosts starry false Solomon's-seal, sand violet, bearberry, and fireweed. Designated a scientific and natural area in 2002, the Minnesota Point Pine Forest Scientific and Natural Area protects 18 acres of native old-growth pines and habitat for several rare and tiny fern species in the genus Botrychium.
A footpath through the SNA eventually leads to dunes where a few hardy and specialized plants survive. Dune inhabitants include sand cherry (Prunus pumila) and beach heather (Hudsonia tomentosa).
One warm day at Park Point, I lay down on the sand to photograph one of the fiercest predators on the dunes—a half-inch-long hairy-necked tiger beetle (Cicindela hirticollis rhodensis). Its Minnesota range is limited to Park Point, and the vulnerability of its sandy habitat to disturbance and development has led to its listing as a species of special concern in Minnesota. This species and its more common cousin, the bronzed tiger beetle (C. repanda), both make their living stalking and pouncing on insects as large as themselves. Powerful jaws efficiently make mincemeat out of prey. Their equally predacious larvae create conical pits in the sand to trap prey. Insect victims tumble in and slide to the bottom of the pit, where they are met by a set of formidable jaws.
Many dune critters are mottled gray, white, and black—perfect camouflage for disappearing against a background of quartz, feldspar, and hornblende sand grains. The mottled sand grasshopper (Spharagemon collare) is aptly named and common on Great Lakes dunes. The award for best camouflage goes to the cryptically colored beach wolf spider (Arctosa littoralis). This arachnid seems to appear out of nowhere, running across the sand, and then, just as quickly, stopping and vanishing into the sandy substrate. It forgoes a web of any kind. Instead, like its wolf namesake, the wolf spider captures prey in short bursts of speed.
In spring and fall, birds exhausted by long migratory flights might see the spit as an oasis. Shorebirds migrating from the Atlantic or Gulf coasts probably feel right at home along the beaches of Park Point. On late spring strolls, I watch sheeplike flocks of sanderlings scurry ahead of me. They dash for food in the wet sand as a wave retreats and then hustle back up the beach, just inches ahead of the rolling surf.
During their northbound migration, black-bellied plovers take a break to feed and rest along Park Point. American golden-plovers pause here during their epic 10,000-mile journey from wintering grounds in Brazil, Uruguay, Paraguay, and Argentina to their breeding grounds on the tundra of northern Canada and Alaska.
My favorite to watch, though, is the ruddy turnstone. This harlequin-marked beauty walks deliberately down the shoreline, picking at invisible-to-us invertebrates, refueling en route to its Arctic breeding grounds.
In mid- to late May, birders long for the type of day that most folks hate—dense, pea-soup fog. Like pilots without autopilot navigation, birds are grounded in this weather. If fog lasts several days, Park Point becomes a real migrant trap, trees dripping with birds. On several memorable fallouts, birders have counted 25 species of warblers in a single morning. During another fallout, a group counted more than 100 species on a one-mile stretch of the point.
Rarities recorded on Park Point are many. The highlight reel would include first state records for Wilson's plover and long-billed murrelet. Rare strays from the south include snowy plover, scissor-tailed flycatcher, vermillion flycatcher, and black-throated gray warbler. Arctic species include slaty-backed gull, ivory gull, long-tailed jaeger, king eider, and gyrfalcon. According to local bird guru and guide Kim Eckert, more than 300 of the 438 bird species ever recorded in Minnesota have been seen on Park Point.
Not surprisingly, the oceanlike Lake Superior probably suits the marauding parasitic jaeger I'd been watching. The frantic ring-billed gull could not shake the harrying jaeger. Finally, the gull did the one thing it knew would rid itself of the jaeger: It vomited up its last meal. Switching targets, the jaeger performed a beautiful nosedive and scooped up the brown blob in midair. Dinner!