On the gravel bar below the former Iron Gate Dam, on the lower Klamath River about twenty kilometres south of the California-Oregon border, a yellow warbler was singing on the afternoon of May 8, 2026, from the top of a coyote willow that had germinated, at the latest, in the spring of 2025.
The willow was a metre and a half tall. The bird was paired. The river ran clear past the gravel bar at about thirty cubic metres per second, which is low for May but not anomalous.
The dam itself had been a hundred and seventy-three feet tall, a concrete arch built in 1962. It came out in 2024, the last of four dams removed on the lower Klamath in an effort that began with a settlement agreement in 2010 and ended with the largest dam-removal project in United States history.
What the river has been doing since is something the restoration community had been planning for, in models and on paper, for over a decade. What the bird community has been doing is what is now beginning to be documented.
Edith Crale spent the first week of May 2026 walking transects along approximately twelve kilometres of the lower Klamath corridor between the former Iron Gate site and the confluence with the Shasta River. The work was a joint project of Roost and the Klamath Bird Observatory, which has been running long-term point counts on the river since 1994.
The headline finding, in advance of the formal analysis, is the rapid arrival of riparian-obligate species onto recently exposed gravel and the slower but real return of mature-cottonwood specialists to reaches where the cottonwood gallery had been suppressed for half a century.
Yellow warblers are the most obvious. Willow flycatchers, which had been nearly absent from the corridor below the dams in the 2000s, are now being detected on multiple territories. Lazuli buntings have moved into the early successional shrub layer on the exposed reservoir footprints upstream.
The mechanism is structural. The dams, while they stood, had cut off the sediment and flow regime that builds and maintains a working riparian corridor. Below them, the river had been running clear and cold, with armored gravel and almost no willow establishment. Above them, the reservoirs had drowned the corridor entirely.
With the dams gone, the system is doing what it does. Sediment is moving. Gravel bars are forming and being rebuilt. Willows, which produce seed by the billions and germinate on bare wet sand, have established in dense stands across the former reservoir footprints and across new bars below the dam sites.
Cottonwood is slower and more particular. It needs a specific seedbed: bare moist sand, exposed in late spring as flows recede, in full sun. The new flow regime appears to be producing this, but cottonwood establishment is patchy and will be the slow story of the corridor across the next twenty to forty years.
The bird community is responding on the willow timescale, not the cottonwood one. The willow flycatcher and yellow warbler want exactly the dense shrubby willow that has come up in the last two seasons. The yellow-breasted chat, which had been a rare bird in the lower Klamath corridor, is now being recorded regularly on the upstream reservoir footprints.
The Klamath Bird Observatory's long-term data set, which began under John Alexander in 1994, makes the comparison possible. The 1995-2010 baseline shows a riparian bird community thin in willow obligates and dominated by generalists. The 2025-2026 early post-removal data show a sharp uptick in willow obligates and a slight decline in generalists, consistent with structural change.
It is too early to call any of this a recovery. Recovery, in the riparian sense, will take decades. What it is, instead, is the beginning of a long re-arrangement that the river is doing on its own once the structural impediments have been removed.
The restoration practitioners have learned to step back. The Yurok Tribe, which holds substantial cultural and legal interest in the lower river and which was a primary mover in the dam-removal coalition, has favoured what it calls a light-touch approach: monitor, document, intervene only where needed to address specific problems, otherwise let the system do its work.
There are specific interventions. Invasive plant management has been substantial on the former reservoir footprints, where dense stands of medusahead and yellow star-thistle had to be controlled before willow could establish. Some seeding of native grasses has been done. Beaver have been encouraged where they have shown up.
Beaver matter here. The lower Klamath corridor had supported beaver historically and had lost almost all of them by the mid-twentieth century. The early returns from monitoring suggest beaver are now recolonizing several reaches, with attendant effects on the riparian water table and willow establishment.
The bird community will follow the beaver where the beaver lead. Yellow warbler, willow flycatcher, common yellowthroat, and song sparrow all benefit from the wetland complex that beaver create.
Crale's transect notes from May 8 include a count of eleven willow flycatcher territories across the twelve-kilometre walk. The pre-removal baseline was zero to two territories in the same reach.
The corridor is not a finished thing. It will not be finished in our lifetimes. What it is, eighteen months after the last dam came out, is a working argument that the largest river restoration in the United States is producing exactly the structural recovery the modeling predicted, and that the birds, on the willow timescale, are already there.
On the evening of May 8, downstream from the Iron Gate site, a black-headed grosbeak sang from a stand of older alder that had survived the dam years. A common merganser drifted past on the current. The river kept moving sediment to the next bar.
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