Clayey High Lime Till Plains

Monarchs (Danaus plexippus) have been recorded nearly every day this week along parks and green corridors, with three sightings on July 28 alone. This is the summer breeding generation — the one whose offspring will undertake the thousand-mile autumn flight to central Mexico starting in late August. That migration depends on host plants being available now, and they are: swamp milkweed was logged at more than a dozen sites across the area this month, including along the Huron River in Ann Arbor on July 27 and at Liberty and Eberwhite on July 28. Common and butterfly milkweed turn up just as often. What the records show is co-occurrence — adult butterflies and their larval host plant in the same corridor in the same week. They don't tell us whether any given stand is in flower, or whether a female has used it. Monarchs lost roughly ninety percent of their North American population between the 1980s and early 2000s and are flagged as threatened, which is what makes each of those milkweed patches worth knowing about.Conditions this week have been favorable. Air quality is good — PM2.5 AQI at 40, ozone AQI at 23 — and the Huron River at Ann Arbor is running steadily at around 140 cubic feet per second, keeping wetland edges moist and milkweed accessible.

Ninety-four facilities hold active Clean Water Act discharge permits within about 15 kilometers of here, and nearly a quarter of them are currently in significant noncompliance. What stands out isn't the raw count, it's the roster. There is no single industrial villain to point a finger at; instead there's a scatter of hotel and apartment swimming pools, apartment-complex stormwater permits, the Saline municipal storm sewer system and its counterpart, the Ann Arbor municipal storm sewer system, a water treatment plant at Austin Commons II, and one manufacturer, Plastechs. Among the pools alone, violations turn up at properties like Weber's Inn, the Marriott TownePlace Suites, the Hyatt Place, the Holiday Inn Express & Suites pool, the Homewood Suites pool, and the Hampton Inn & Suites, alongside apartment-complex permits such as Broadway Park West, Foundry Lofts, The Yard, University Trails, The Standard at Ann Arbor, Mill Creek One, Traverwood-Oakcliff Apartments, The George Apartments, Woodview Commons, plus smaller pool permits at 950 Greene Street, Big Blue Swim School, North Oaks, and Bicentennial Park. Sixty of these permittees logged violations in the past year, and sixty have actually been inspected, so the gap here isn't a lack of oversight. It's that only one facility faces any formal enforcement action, and total penalties assessed across all ninety-four permits add up to zero dollars.That matters because the water downstream isn't starting from a clean baseline. Twenty-two of forty-nine nearby water bodies, including the pond chain this watershed feeds, are already listed as impaired and required to have cleanup plans. This landscape sits within the Clayey High Lime Till Plains, a flat, poorly drained till landscape within the broader Eastern Corn Belt Plains, where heavy clay subsoils shed water quickly across the surface rather than letting it infiltrate. Low-grade noncompliance from dozens of small permit holders doesn't show up as a dramatic spill, but it accumulates the same way runoff does: a little excess chlorine here, a little untreated stormwater there, spread across a whole city's worth of pools and parking lots, feeding into water already on the state's impaired list.For several of the flagged permits, including the lone manufacturer and both municipal storm sewer systems, the specific pollutant and exceedance size aren't visible in the compliance record, only the noncompliance designation itself, and the Saline River near Saline, MI gage showed normal flow with no water-quality readings available to check against. So the exact mechanism connecting these violations to downstream impairment can't be confirmed. But the pattern, one in four permits out of compliance with no penalties attached, is documented, and it describes a watershed where enforcement isn't keeping pace with the paperwork.

Air quality hit unhealthy levels today—PM2.5 climbing to AQI 110—at precisely the moment when breeding birds are metabolically stretched to their limit. Nestlings demand constant feeding, and parents must spend their days in sustained flight through an atmosphere thick with industrial emissions and wildfire smoke. Avian lungs are uniquely sensitive to particulates—more so than most mammalian respiratory systems—making this timing especially precarious.The stagnant summer air has trapped pollutants close to the ground, preventing dispersal. For birds mid-fledging cycle, the cost is real: impaired oxygen uptake during the most energy-demanding weeks of the year. The margin between survival and stress in a breeding colony is rarely wide.

The river dropped from 12 to 6 feet this week, flushing a surge of flood water through the chain of ponds downstream — Barton, Argo, and Geddes — during the height of amphibian breeding season. All three ponds are already officially impaired, their ecology compromised. The timing could not be worse.The city's own stormwater permit is now in violation, pushing unchecked runoff into an already-stressed system at the moment when Spring Peepers, American Toads, and other breeding amphibians depend most on stable shallow water. The disturbance will scatter eggs and larvae, and the influx of sediment and pollutants will further degrade habitat that these ponds can barely support.

A storm surge has driven the river to twelve feet — nearly double its recent baseline — arriving squarely in the window when fish and aquatic insects are most vulnerable. Peak breeding season coincides with peak runoff, and nutrient loads from swollen stormwater outfalls can obliterate entire cohorts of eggs and early larvae in a matter of hours.The timing compounds an existing problem. Most waters in the immediate catchment are already classified as impaired, and the stormwater management system that feeds them is running out of compliance with its permit. In a landscape shaped by agriculture and urban sprawl, extreme rainfall events have become a reliable mechanism for ecological collapse — the system moves fast enough that recovery mechanisms simply cannot keep pace.

Along the roadsides and field edges near Ann Arbor, common milkweed is pushing up fast. The stems are thick and pale green, the leaves broad and soft, still growing toward their full summer size. This is the plant monarchs are looking for right now, and a few of them have made it here.Monarchs arriving in the Ann Arbor region in early summer are the first generation born after the overwintering population left Mexico in spring. They followed the milkweed north, breeding as they went, and their offspring are the ones moving through here now. A monarch searching for a place to lay eggs is not wandering. She flies low over vegetation, dropping toward plants, hovering briefly, then moving on. When she lands on a milkweed leaf, she presses the underside of her front feet against the surface. Monarchs have chemoreceptors in their tarsi, sensory structures that detect the chemical signature of milkweed on contact. If the plant is right, she curves her abdomen under the leaf and attaches a single egg, pale green and ridged, small enough to sit on a fingernail. Then she moves to the next plant.She rarely lays more than one egg per plant. This is not accidental. Monarch caterpillars are solitary feeders, and a single milkweed stem does not have enough leaf mass to support more than one caterpillar through all five of its growth stages. Spreading eggs across multiple plants reduces competition and increases the chance that each larva survives to pupate. The eggs hatch in three to five days. The caterpillar that emerges eats its own eggshell first, then begins working through the leaf. It feeds on nothing else. Common milkweed produces cardenolides, compounds toxic to most insects and vertebrates, but monarch caterpillars have a modified version of the cellular protein that cardenolides normally disrupt. They can consume the toxin without harm, and the cardenolides accumulate in their bodies. Birds that have eaten a monarch and experienced the resulting nausea tend to avoid them afterward. The bold orange and black patterning of the adult makes that association easier to remember.Common milkweed is doing well here in early summer because it is well suited to disturbed edges, roadsides, and old fields, the same habitats that have expanded as agricultural and suburban land use has changed the region. The plant spreads by rhizome, forming colonies that return reliably each year. Monarchs can find those colonies across large distances, though how they do this at the scale of a landscape is not fully understood. They respond to visual cues and plant chemistry, but a butterfly covering miles of mixed terrain, locating scattered milkweed patches, is doing something that researchers are still working to characterize precisely. What is clear is that the match between monarch arrival timing and milkweed leaf-out is close. Early summer milkweed leaves are young and high in water content, which benefits the caterpillars. As the season advances and the leaves toughen, they become less suitable. The timing works because both the insect and the plant are responding to the same seasonal cues: temperature and day length.If you are near a field edge or a patch of open ground, look for milkweed. The stems stand upright, often in clusters, with opposite leaves and a distinctive oval shape. If monarchs are moving through, a female may be working the patch right now, low and methodical, pausing at each plant. The leaves in the sun smell faintly bitter if you brush them. That bitterness is the cardenolide, the same compound the caterpillar is built to handle and that makes the adult butterfly something most birds learn to leave alone.

Rapids Clubtail damselflies (Phanogomphus quadricolor) have returned to the swift reaches this early summer — seven sightings over the week of May 31 through June 7, an encouraging sign for this threatened species' resilience in the region.Their presence here is striking given the upstream context. Both the impounded waters that bookend this stretch—Barton Pond and Argo Pond—carry pollution listings and don't support the demanding habitat this clubtail needs. Yet the free-flowing gravel and cobble habitat between them, where current scours the riverbed clean, remains viable. The river ran 2.5 times its recent average flow on the day of observation, surging to 12.46 feet, conditions that favor both the damselflies and the aquatic prey they depend on.This is a quiet reminder that ecological recovery isn't binary. A threatened species can persist in refugial pockets even when surrounded by degraded water, so long as those patches of clean current remain unbroken.

Step outside into the long light of early summer, where the air holds warmth even as evening approaches. The foxglove beardtongue stands tall in the meadow edges around Ann Arbor, its white tubular flowers arranged in neat tiers along sturdy stems. Each bloom opens wide at the mouth, revealing purple guidelines that lead deeper into the throat.On these flowers, margined leatherwing beetles work with methodical purpose. The beetles are soft-bodied and elongated, their wing covers a warm orange-yellow bordered by dark margins that give them their name. They move across the flower faces with deliberate steps, their antennae constantly probing. Unlike the quick visits of bees or the hovering of flies, these beetles settle in. They chew pollen directly from the anthers and lap nectar from the flower's base, their flexible bodies allowing them to reach deep into the tubular blooms.The foxglove beardtongue depends on this partnership. The plant produces no scent to attract pollinators from a distance, instead relying on visual cues and the promise of abundant resources. Its flowers remain open for several days, giving beetles time to discover them and return. As the leatherwings feed, pollen grains stick to their fuzzy bodies and legs. When they move to the next flower, or the next plant, they carry this genetic material with them. The beetle's thorough feeding style means it contacts both anthers and stigma reliably, making it an effective pollinator despite its unhurried approach.This relationship peaks now, in early summer, when both species reach their seasonal crescendo. The beardtongue has been building toward this moment since its leaves emerged in spring. The plant invested energy in tall stems and multiple flower spikes, each capable of producing hundreds of seeds if properly pollinated. The beetles, meanwhile, have been feeding on other flowers throughout late spring, building the energy reserves they need for reproduction. On warm afternoons, you might find several beetles on a single beardtongue plant, males and females feeding side by side, occasionally pausing to mate before returning to their methodical harvest.The timing matters. Foxglove beardtongue blooms for only a few weeks, and the margined leatherwings must synchronize their adult emergence with this narrow window. Too early, and the flowers are not yet open. Too late, and the blooms have faded, the plant's energy redirected toward seed development. But when the timing aligns, as it does now, the meadow becomes a quiet theater of mutual benefit. The white flowers glow against their green backdrop, and the golden beetles move among them like small flames, carrying the future of both species in the pollen that dusts their bodies. Close your eyes and listen for the soft sound of their movement, the barely audible rustle as they shift from bloom to bloom in the warm, still air.

The air above the Huron River carries a tension that wasn't here a week ago. Lilacs finish their bloom along the banks, their heavy sweetness mixing with the green smell of new leaves. But something faster cuts through this settled spring air.A peregrine falcon sits motionless on the water tower, scanning the canopy below. The bird is sleek and compact, built for speed in a way that makes every other raptor look clumsy. Its dark head turns in small increments, tracking movement sixty feet down where bay-breasted warblers work through the maples. These small songbirds have been flying north for days, following the insect emergence that comes with warming weather. They move through the trees in loose groups, gleaning aphids and caterpillars from the newly expanded leaves. The warblers are tired from their night flight, focused on feeding, and predictable in their movements through the mid-canopy. The falcon knows this.Peregrine falcons nearly disappeared from Michigan forty years ago, poisoned by DDT that thinned their eggshells past the point where chicks could survive. The population collapsed to nothing before the pesticide was banned and captive breeding programs began releasing young birds back into the wild. Now they nest on bridges and tall buildings throughout the region, their numbers recovered enough that seeing one hunt along the river is no longer remarkable. But what they hunt has changed. Before pesticides, peregrines fed mostly on shorebirds and waterfowl over open water. Now they take advantage of the spring migration bottleneck, when thousands of small songbirds move through narrow corridors of remaining forest. The warblers that pour through Ann Arbor each May represent a concentrated food source that wasn't available to falcons a century ago, when continuous forest spread across the region. Migration routes have compressed into fragments, and falcons have learned to position themselves along these aerial highways.The strike happens faster than the eye can follow. The falcon drops from its perch and accelerates into a shallow dive, reaching speeds that would tear apart a less perfectly designed bird. It doesn't stoop straight down like it would over open water, but angles through the canopy gaps with surgical precision. A bay-breasted warbler, focused on a cluster of emerging moths, has no time to react. The impact is silent from this distance, over in an instant. The falcon carries its prey to a horizontal branch and begins feeding while the other warblers continue their search through the leaves, already resuming the rhythm that migration demands. Yellow-throated warblers work the oak bark nearby, their longer bills probing for insects the bay-breasted birds cannot reach. They seem unaware that one of their traveling companions has just been removed from the journey.The water below reflects the full canopy now, solid green broken by patches of sky. Listen for the sharp kek-kek-kek call that announces a falcon's presence, or watch for the sudden stillness that falls over the smaller birds when a predator appears overhead. The hunt continues in the space between the flowering trees and the water, where speed meets the slow patience of migration.