Corvallis Science and Nature: Rare Bird Visits Corvallis, Maintaining Oak Woodlands, When Trees Aren’t the Answer 

 New Bird for Benton 

Corvallis got an unexpected visitor this week that sent area birders rushing on to OSU’s campus. The green-tailed towhee, pictured above, is a large sparrow that breeds in the high deserts of central and eastern Oregon and migrates south as far as southern Mexico in the winter. One of its close relatives, the spotted towhee, is a regular in and around Corvallis, but before last Monday, green-tailed towhees had never been recorded in Benton County, and only very rarely anywhere east of the Cascades. (the last sighting in Linn County was over 30 years ago).   

OSU student Nina Ferrari first spotted the towhee near Peavy Hall, and quickly reported it to a WhatsApp group for local birding rarities. That brought a number of hopeful birders to campus to get their own look. According to local birder Hendrik Herlyn, the little lost bird was unbothered by passing students, but was spooked at one point by one of the university’s food delivery robots.Since the sighting was confirmed and the bird photographed, the towhee can officially be added to Benton’s bird list, as the 345th species ever recorded in the county.   

When Trees Aren’t the Answer 

The green-tailed towhee’s usual breeding habitat is on the dry side of the Cascades and across the arid interior west. If you’ve ever driven across eastern Oregon, it might seem like we have all the sagebrush steppe we could ever want, but it’s actually a diminishing and endangered habitat, and one of the reasons might be just as surprising: trees. Just as deforestation is a critical problem in many wetter areas of the world, certain trees growing where they don’t belong can cause serious issues in drier regions. An OSU-led study that came out this week adds to our understanding of how this happens.  

Juniper and Piñon pine have been invading sagebrush steppe for decades, with a range of consequences including decreasing habitat for sagebrush-dependent species and changing patterns of wildfire. Removing them has become a common tool in habitat restoration, but data has been limited on how and why it works. This new study, published in the journal Ecosphere, tested the effect of removing trees on both native plants and introduced cheatgrass, another widespread invader of sagebrush habitat. The researchers found that the trees dry out their local soil, which in turn suppresses the native plants, while leaving the more drought-tolerant cheatgrass much less affected. It’s another piece of evidence that while trees are valuable and important globally, tree planting as a solution to both climate change and habitat loss has to take the local habitat into account. The answer has to be the right tree in the right place, and sometimes, no tree at all.  

Making Room for Oaks 

You don’t have to look all the way to eastern Oregon to see examples of helping threatened habitat by limiting certain kinds of trees. Right here in Corvallis, local nonprofit Greenbelt Land Trust is looking for volunteers to help maintain oak forest by cutting back faster-growing commercially grown conifers like Douglas fir. Oak woodlands once covered over 400,000 acres in the Willamette Valley, and less than 5% of that survives today. You can help Greenbelt Land Trust with their next “conifer hunt” on Dec. 17 at Bald Hill Farm. Register here.  

Resource for Pest-Weary Growers 

With the weather getting wet and cold again, most of us aren’t thinking much of gardening right now. But when it’s time to put seeds in the ground and dirt into pots again next spring, there will be a valuable new tool for both farmers and gardeners to deal with some of the pests that trouble our local crops.  

OSU Extension Service recently launched its new Solve Pest Problems website to help growers of all levels manage pests effectively, safely, and with as few chemicals as possible. There are sections for insects, mammals, invasive plants, and plant diseases.The whole site is organized around a “look first” approach, and one of the most useful and innovative sections is a guide to help decide whether an intervention is necessary at all. There is a tendency to see one pest and reach for a solution, when sometimes, depending on the pest and time of year, the problem can sometimes take care of itself.   

By Ian Rose