Nestled in the Brambles: Rethinking Restoration for Riparian Birds
- Elva Manquera
- Jul 16
- 4 min read
In the shaded tangles along Oregon’s creeks and rivers, a quiet drama is unfolding. Birds are nesting, ecosystems are shifting, and one team of biologists is asking whether a well-intentioned act of restoration might be inadvertently reshaping the story of riparian bird communities.
It started with a puzzle. Years ago, data from the Trinity River Project revealed that a surprising number of bird nests—about half of all nests for the riparian species being studied, and an astounding 90% of Yellow-breasted Chat nests—were tucked into the dense sprawl of non-native Himalayan blackberry.
“That realization caught our attention,” says Dr. Sarah Rockwell, a research biologist with Klamath Bird Observatory. “We started wondering—what happens to the birds when we remove the blackberry?”
Clusters of restoration sites in Oregon’s Rogue Valley—particularly at Cantrall Buckley Park and Hamilton Road with the Applegate Partnership and Watershed Council—offered the perfect outdoor laboratory. With blackberry removal planned at one of the sites this coming winter, the opportunity to study before-and-after effects on birds was too good to pass up.
The Science of Shrub and Song
At its core, the project examines how blackberries—and their invasive nature—affect bird abundance, nesting success, and nestling health. The team uses spot-mapping to track territory density, nest-searching to monitor reproductive success, and nestling weight as a metric of health. For the first time at KBO, insect sampling has been added to assess shifts in food availability, and vegetation surveys document blackberry cover at each site. While birds frequently choose nest sites in blackberry, we don’t know if it provides ample insect food resources as native plants, or if nestlings raised in blackberry-dominated areas are as healthy and robust.
Some field challenges require creative solutions. “You can’t always see inside higher nests to count the eggs or chicks,” Sarah explains, “so we built a four-meter collapsible pole with a car mirror duct-taped to it. Low-tech, but effective.”
These methods mirror recent community science efforts. Since 2021, more than fifty local volunteers have assisted in surveying seven riparian sites between Ashland and Central Point for the Bear Creek Community Bird Survey. The focus? A set of thirteen indicator species that together reflect the ecological health of these riparian habitats.
Why Riparian Zones Matter
Riparian areas—those slender green ribbons hugging streams and rivers—make up only 1% of Oregon’s land base, yet support a large share of its birdlife. They’re especially vital for shrub-nesting species such as Yellow Warblers and Yellow-breasted Chats.
In that 2022 Bear Creek Community Bird Survey, only one site—Ashland’s North Mountain Park—recorded ten or more focal species during the breeding season. This was not surprising given the recent impacts of the Almeda Fire and the resulting temporary loss of habitat. However, even Dean Creek, which had avoided wildfire damage, saw a decline in focal bird species after its blackberry-dominated shrub layer was cleared.
Restoration With Birds in Mind
That message resonates strongly with Sarah. “If you remove blackberries before birds arrive in spring, they’ll look elsewhere to nest that year. The temporary loss of shrubs can be worth it for long-term gains in native plant diversity. But if you clear it in May or June, you will likely be destroying active nests.”
The field team hopes their work will help restoration partners fine-tune their practices—avoiding vegetation removal during the nesting season, replanting with native shrubs that provide similar nesting habitat, and reshaping perceptions of what a healthy riparian corridor looks like.
More Than Just Aesthetic Choices
One common misconception is that a tidy environment equals a healthy one. Sarah offers a gentle pushback. “A lot of western riparian birds in population decline are shrub nesters. They need dense, messy, multi-layered habitat, which can be interspersed with more open areas—but a manicured, lawn-like landscape does not provide enough habitat value.” She emphasizes that these habitats support not only birdlife but broader ecological processes, like filtering runoff, shading and cooling streams, and providing woody debris for fish habitat.
Community involvement is key. Along Bear Creek, citizen scientists tallied 151 bird species and 77,000 eBird records from 2021 to 2022—a testament to the region’s biodiversity and the role residents can play in its protection.
Field Moments and a Deeper Mission
Despite the thorny work, Sarah finds joy in the day-to-day tasks. “Nest-searching is like finding one of nature’s treasures,” she says. “The parent birds don’t want you to find them and they can be quite sneaky—but once you learn how to look, each new nest you find is extremely satisfying, and contributes to the larger dataset.”
One recent moment stood out: two field techs spotted a Brown-headed Cowbird attempting to parasitize a nest, only to be driven off by fiercely protective parents. They were able to locate the nest this way, which was a first! Another highlight has been seeing all of the different styles of nest locations used by even the same species – for instance, Song Sparrow nests have been found in Himalayan blackberry, Pacific ninebark, willows, vines against trees, flood-deposited dead vegetation, and even another invasive: reed canary grass. Sarah says, “It’s unknown if the species we’re studying prefer blackberry nest sites, or if they’re just adapting to what’s available. We’re building a catalog of nests built in native plants so we can give partners a picture of the vegetation species and structure that support riparian shrub-nesting birds.”
These anecdotes reflect the broader story: decisions about blackberry removal must consider both its negative ecological impacts and its contribution to bird habitat in our already scarce riparian areas. We must be careful not to displace the very species we hope to protect. Pairing removal with thoughtful planning can support native vegetation regrowth and songbird resilience.
A special thanks to Elva & Klamath Bird Observatory for contributing this article to our newsletter and website. Learn more about KBO and restoring riparian habitats at the links below:
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